Ampere
An Ampere is a measurement of electric current. Amperage (A) signifies the rate of electron flow through a conductor, and is a fundamental unit of the International System of Units (SI). Every PCBA component boasts a current rating, specifying the maximum safe amperage it can handle. Exceeding this rating can lead to overheating, damage, or even fires. Understanding amperage is vital for designing PCBs that deliver sufficient current to power components without overloading traces or the power supply.
Categories: PCBA Manufacturing
Analog Signal
Within a PCBA (Printed Circuit Board Assembly), analog signals are electrical currents or voltages that continuously vary over time, corresponding to real-world phenomena. Unlike digital signals with discrete voltage levels (0 or 1), analog signals can take on an infinite number of values within a specific range.
Categories: PCBA Manufacturing
AOI, Automated Optical Inspection
Automated Optical Inspection (AOI) is a non-contact, in-line technology used extensively in PCB manufacturing for inspecting assembled circuit boards for defects. It utilizes high-resolution cameras and powerful image analysis software to automatically detect a wide range of issues. AOI systems can identify missing components, misplaced parts, incorrect solder joints, polarity errors, and even cosmetic imperfections on the PCB. By integrating AOI throughout the manufacturing process, manufacturers can catch and correct defects early, significantly improving production yield and ensuring consistent quality for their PCBs.
Categories: PCBA Manufacturing
AQL, Acceptable Quality Limit
In PCB manufacturing, Acceptable Quality Limit (AQL) is a statistical concept used in quality control. It defines the maximum tolerable percentage of defects considered acceptable for a specific batch of PCBs. Essentially, it sets a benchmark for the allowable number of faulty boards.
Categories: PCBA Manufacturing
Aperture
In PCB manufacturing, the term "aperture" has two main contexts:
Historical Definition (Photoplotting):
In traditional PCB manufacturing processes, an aperture referred to a small, shaped opening in a thin, plastic disc. This disc, known as an aperture wheel, rotated in a vector photoplotter. Light shone through the chosen aperture shape, exposing specific areas on a sheet of photographic film. The film pattern, once developed, served as a blueprint for creating conductive traces and pads on the PCB. Different aperture shapes existed for various features, like rectangular pads, circular holes, or custom shapes.
Modern Definition (CAM Data):
Today, with advancements in technology, photoplotters often utilize lasers instead of physical apertures. However, the term "aperture" persists in the realm of Computer-Aided Manufacturing (CAM) data. Here, an aperture refers to a set of data within a Gerber file that defines the size, shape, and function of an element on the PCB layout. This data can include:
- Shape: Square, rectangle, circle, or custom outline.
- Dimensions: Width and height for rectangular shapes, or diameter for circles.
- Function: Defines whether the aperture is used to create a pad (flashing light) or a trace (drawing light).
Modern CAM software allows defining and managing aperture libraries, ensuring a consistent and accurate representation of design elements in the final PCB.
Categories: PCBA Manufacturing
Aperture List
An aperture list, also known as a D-code list, is a text file used in PCB manufacturing. It acts as a dictionary that defines the various shapes and sizes used to represent features on a printed circuit board (PCB) layout.
With advancements in Gerber formats (RS274X), it's becoming increasingly common to embed aperture information directly within the Gerber files. This eliminates the need for separate aperture lists.
Categories: PCBA Manufacturing
Aperture Wheel
An aperture wheel was a mechanical component used in a vector photoplotter. These photoplotters created a film pattern that served as a blueprint for etching conductive traces and pads on the PCB.
With advancements in technology, aperture wheels have been largely replaced by:
Laser Photoplotters: Modern photoplotters utilize lasers instead of physical apertures, offering greater flexibility and precision.
CAM Data: Aperture information is now embedded directly within the Gerber files used for PCB manufacturing.
Categories: PCBA Manufacturing
ASCII
ASCII (American Standard Code for Information Interchange) is a fundamental concept in computing. It's a character encoding standard that assigns a unique numerical code to letters, numbers, punctuation marks, and other symbols. This allows computers to represent and exchange text information consistently.
Why ASCII is Important:
Universal Understanding: ASCII established a common language for computers to understand and process text data.
Early Communication: It played a critical role in the development of early computer networks and data exchange.
Legacy Systems: Traces of ASCII's influence are still present in many computer systems and file formats.
Categories: PCBA Manufacturing
Assembly
PCB assembly, also known as printed circuit board assembly (PCBA), is the process of transforming a bare PCB into a functional electronic circuit. It involves several key steps:
- Components are placed on the PCB according to the design (manual or machine).
- Soldering attaches components with a metal alloy melted onto pads.
- After soldering, the PCB is checked for correct assembly and soldering quality (automated and manual inspection).
- Cleaning removes leftover material from soldering to prevent future problems.
High-quality PCB assembly is critical for the proper functioning of electronic devices. It provides:
- Strong Electrical Connections: Secure soldering creates reliable electrical connections between components and the PCB traces.
- Functionality: Correct placement and soldering of components are essential for the circuit to operate as intended.
- Durability: Proper assembly techniques lead to robust PCBs that can withstand environmental stresses and function reliably over time.
Categories: PCBA Manufacturing
Assembly House
In the electronics industry, an assembly house, also known as a PCB assembly (PCBA) house or contract manufacturer (CM), is a company that specializes in the assembly of printed circuit boards. They offer a range of services, typically including:
- Component Procurement: Assembly houses can source electronic components based on the customer's bill of materials (BOM).
- PCB Assembly: They handle the entire printed circuit board assembly process, from component placement and soldering to inspection and testing. This can involve various assembly techniques for through-hole and surface mount components.
- Programming and Testing: Some assembly houses offer additional services like pre-programming flash memory or performing functional testing of the assembled boards.
Benefits of Using an Assembly House:
- Expertise: Assembly houses have the expertise and equipment necessary for efficient, high-quality PCB assembly.
- Scalability: They can handle production volumes ranging from prototypes to large-scale manufacturing runs.
- Cost-Effectiveness: Utilizing an assembly house can be more cost-effective than setting up an in-house assembly line, especially for low- to medium-volume production.
Categories: PCBA Manufacturing
ASTM
ASTM, formerly known as the American Society for Testing and Materials, is now ASTM International. It's a globally recognized organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.
Categories: PCBA Manufacturing
ATE, Automated Test Equipment
In PCB manufacturing, Automated Test Equipment (ATE) refers to sophisticated computer-controlled systems used to automatically test assembled printed circuit boards (PCBs). ATE plays a crucial role in ensuring the quality and functionality of electronic devices.
Categories: PCBA Manufacturing
Auto-Router
An auto-router, in PCB design software, is a computer program that automatically attempts to route the electrical connections between components on a printed circuit board (PCB).
Categories: PCBA Manufacturing
AWG, American Wire Gauge
AWG (American Wire Gauge) is a standardized system for denoting the diameter of round, solid electrical wires in North America. Unlike most measurement systems where a higher number signifies a larger size, AWG works inversely. In other words, lower AWG numbers represent thicker wires with a larger diameter and greater current carrying capacity.
Categories: PCBA Manufacturing
Back Drilling
In PCB manufacturing, back drilling is a precise machining process used to remove a specific portion of material from the inner layers of a multilayer PCB. It primarily targets a feature called a via stub.
Here's a breakdown of back drilling and its role in PCB functionality:
- Via Stubs: When plated through-hole vias (electrical connections that pass through the PCB) are formed, a small unused section of copper barrel remains on the opposite side of the drilled hole. This remnant is called a via stub.
- Impact of Via Stubs: While seemingly insignificant, via stubs can introduce unwanted electrical effects, particularly in high-speed circuits. They can cause signal reflections that distort or weaken the signal traveling through the via.
- Back Drilling to the Rescue: Back drilling addresses this issue. It utilizes a computer-controlled machine with a very fine drill bit to precisely remove the via stub from the desired inner layer(s) of the PCB.
Benefits of Back Drilling:
- Improved Signal Integrity: By eliminating via stubs, back drilling ensures a more consistent electrical path for signals, minimizing signal reflections and enhancing overall signal integrity in high-frequency applications.
- Reduced Crosstalk: Minimizing signal reflections also helps reduce crosstalk, which is the unwanted coupling of signals between adjacent traces on the PCB.
- Maintaining Impedance Control: Back drilling can be crucial for maintaining consistent impedance (resistance to signal flow) throughout the via, which is critical for high-speed signal transmission.
Categories: PCBA Manufacturing
Bandwidth
Bandwidth refers to the maximum frequency a signal can pass through a conductor on the PCB without significant distortion or attenuation. It's a crucial factor for ensuring reliable signal integrity in high-speed applications.
Categories: PCBA Manufacturing
Barcode
A barcode is a machine-readable visual representation of data, typically consisting of black bars and spaces of varying widths. In PCB assembly and manufacturing, barcodes are most commonly used for component tracking, WIP (work in progress) tracking, and inventory control.
Categories: PCBA Manufacturing
Baud Rate
Baud rate, measured in baud (Bd), is a unit that signifies the number of symbol events occurring per second during serial communication. This may become significant relative to two key processes: In-System programming (ISP) or Boundary-Scan Testing. Boundary-Scan Testing uses embedded circuitry within components to diagnose faults on a PCB assembly; establishing proper communication between test equipment and the PCB’s boundary scan chain requires setting the correct baud rate.
Categories: PCBA Manufacturing
Bed of Nails
Another name for an In-Circuit Test (ICT) fixture.
Categories: PCBA Manufacturing
Bend Radius
Bend radius refers to the minimum allowable interior curvature (minimum radius) a flexible printed circuit board (FPC) can withstand without permanent damage or compromising its functionality. Several factors influence acceptable bend radius including board thickness, number of layers, and material composition.
Categories: PCBA Manufacturing
Beveled Edge
A beveled edge refers to a PCB edge that's been machined or ground at an angle–typically between 30 and 45 degrees–creating a slant instead of a sharp 90-degree corner. Beveled edges make it easier to insert PCBs into edge connectors or slots within housings by reducing friction. It also can mitigate stress concentrations on PCB corners, reducing the risk of cracks or fractures.
Categories: PCBA Manufacturing
Bias Voltage
Bias voltage refers to a constant voltage applied to a specific point in a circuit to establish a desired operating condition for an active component like a transistor or operational amplifier (op-amp). Proper bias voltage selection can help maintain circuit stability and prevent unexpected behavior caused by variations in temperature or component tolerances.
Categories: PCBA Manufacturing
Binary Code
Binary code is the cornerstone of digital electronics. Using a two digit numbering system (0 and 1), with high voltage level represented by “1” and low voltage level represented by “0”, binary digits form the foundation of encoding and processing information within electronic devices. The building blocks of digital circuits are logic gates, which perform basic operations like AND,OR, and NOT based upon binary inputs, generating binary outputs that determine overall circuit behavior.
Categories: PCBA Manufacturing
Black Pad
Black pad is an undesirable condition caused by nickel corrosion affecting the ENIG surface finish commonly used on PCBs. It manifests as a dark, corroded area on the nickel layer beneath the gold plating. This defect compromises the solderability of the affected pad, leading to potential issues during PCB assembly. Black pad is often difficult to detect visually during initial inspection because the gold layer masks the underlying corrosion.
Categories: PCBA Manufacturing
Blister
A blister is a detrimental defect on a PCB (Printed Circuit Board) that manifests as a localized separation or delamination between different layers of the board. This separation creates a raised area with a hollow interior, resembling a blister. Blisters compromise the structural integrity and electrical functionality of the PCB. Blisters may occur due to improper surface preparation, excessive thermal stress, chemical contamination within the PCB laminate, or moisture absorption and expansion within the PCB layers.
Categories: PCBA Manufacturing
Board House
In the electronics industry, a board house, also commonly referred to as a PCB assembly house, contract manufacturer (CM), or electronics manufacturing services (EMS) provider, is a company specializing in the assembly of printed circuit boards (PCBs). They offer a range of services, typically including:
- Component Procurement: Board houses can source electronic components based on the customer's bill of materials (BOM).
- PCB Assembly: They handle the entire PCB assembly process, from component placement and soldering to inspection and testing. This can involve various assembly techniques for through-hole and surface mount components.
- Programming and Testing: Some board houses offer additional services like pre-programming flash memory or performing functional testing of the assembled boards.
Benefits of Using a Board House:
- Expertise: Board houses have the expertise and equipment necessary for efficient, high-quality PCB assembly.
- Scalability: They can handle production volumes ranging from prototypes to large-scale manufacturing runs.
- Cost-Effectiveness: Utilizing a board house can be more cost-effective than setting up an in-house assembly line, especially for low- to medium-volume production.
Categories: PCBA Manufacturing
BoM, Bill of Materials
In manufacturing, a Bill of Materials (BoM) is a comprehensive, structured list that details all the components, parts, materials, and quantities required to create a product. It serves as a centralized resource for manufacturers, engineers, and other stakeholders involved in the production process.
Categories: PCBA Manufacturing
Boolean Logic
Although boolean logic isn’t directly involved in physical assembly, it plays a crucial role in programming automated test equipment (ATE) that ensures the functionality of PCBs. Boolean logic is a form of algebra dealing with True (1) and False (0) values. Test programs utilize Boolean operators (AND, OR, NOT) to evaluate various signals on the PCB. These operators define the conditions that a circuit must meet to pass the test. A test might check if a specific voltage level is High (1) AND another signal is Low (0) before proceeding to the next test step. By defining complex logical relationships, manufacturers can identify specific failures within PCB assemblies.
Categories: PCBA Manufacturing
Border Area
The term "border area" typically refers to the region on the edge of a printed circuit board where electrical components are not placed. This area is crucial for ensuring proper functionality and manufacturability of the PCB. The border area provides a clear zone for the drilling of holes for component leads and vias, allows solder mask to be applied cleanly and consistently, and offers a buffer zone to protect delicate components during handling and assembly.
Categories: PCBA Manufacturing
Breakdown Voltage
Breakdown voltage refers to two critical applications:
Dielectric Breakdown: This is the maximum voltage an insulating material (dielectric) within a PCB can withstand before becoming conductive.
Semiconductor Breakdown: This is the reverse voltage limit for a semiconductor device (like a diode) before it allows significant current flow in the opposite direction.
Categories: PCBA Manufacturing
Breakout
Breakout refers to two distinct concepts:
- Panel Breakout: This describes the process of separating individual PCBs from a larger panel on which they were fabricated and assembled. Breakout techniques like v-grooves, slots, or fracturable edges, allow for clean and controlled separation.
- Annular Ring Breakout: This refers to a manufacturing defect where the drilled hole on a PCB breaches the surrounding copper pad (annular ring). If the drilling process is misaligned, the hole can extend beyond the pad, creating annual ring breakout. This defect can lead to weak solder joints, electrical shorts, and potential component failure
Categories: PCBA Manufacturing
Burr
A burr refers to a small, unwanted raised edge or sharp projection left behind on the surface of a PCB after machining processes like drilling, routing, or milling. Burrs may be caused by dull or chipped cutting tools, improper drilling or routing parameters, or material delamination. While seemingly minor, if left unchecked burrs may cause electrical shorts, component placement issues, or assembly damage.
Categories: PCBA Manufacturing
Byte
Understanding bytes is crucial because they form the foundation for all the data processed and stored on PCBs. A byte is the most basic unit of digital information in a system. It typically consists of eight bits (binary digits), where each bit can hold a value of either 0 or 1. Bytes are used to represent various types of information within a PCB, including:
- Instruction codes for the microcontroller or other programmable devices.
- Sensor data collected from various components on the board.
- Configuration settings for onboard memory or peripherals.
Categories: PCBA Manufacturing
Calibration
Calibration refers to a crucially important process that ensures the accuracy and reliability of the automated test equipment (ATE) used to verify PCB functionality. Automated Test Equipment (ATE) is calibrated by comparing its readings with a known reference standard. The reference standard is a highly precise instrument with a verifiable accuracy rating. During calibration, technicians adjust the ATE's internal parameters until they closely match the measurement range of the reference standard.
Categories: PCBA Manufacturing
CAD, Computer Aided Design
CAD software plays a crucial role in modern printed circuit board (PCB) design. It allows engineers and designers to create:
Schematics: These are graphical representations of the electronic circuit, depicting the components (resistors, capacitors, ICs) and their electrical connections using symbols and lines.
PCB Layouts: This refers to the physical arrangement of the electronic components and their interconnecting traces on the PCB itself. CAD software provides tools for placing components, routing traces, and defining various design elements like pads and vias.
Categories: PCBA Manufacturing
CAE, Computer Aided Engineering
CAE tools and software programs are valuable assets in modern PCB design. They go beyond the basic layout creation capabilities of CAD software by analyzing and simulating the PCB's performance in depth.
What CAE Offers for PCB Design:
Performance Analysis: CAE tools can simulate the electrical behavior of the PCB design. This allows engineers to analyze factors like voltage distribution, current flow, and power integrity.
Signal Integrity (SI) Analysis: Signal integrity is crucial for high-speed circuits. CAE software can simulate signal transmission characteristics, identifying potential issues like crosstalk or signal reflections that could degrade signal quality.
Thermal Analysis: PCBs can generate heat during operation. CAE tools can help analyze thermal distribution across the board, ensuring components operate within safe temperature limits.
Manufacturability Analysis: Some CAE software incorporates features for manufacturability analysis. This can help identify potential challenges during PCB fabrication, such as issues with solderability or drill hole quality.
Categories: PCBA Manufacturing
CAM Files
In PCB manufacturing, CAM (Computer-Aided Manufacturing) files are a critical data format used to convey the PCB layout information to the fabrication machines. They essentially act as the blueprints that guide the manufacturing process.
There are several key types of CAM files, each encoding specific information for different fabrication steps:
Gerber Files: The most common format, Gerber files represent the copper layers of the PCB. They contain information about the shapes and sizes of copper features (traces, pads, etc.) on each conductive layer.
Drill Files: These files specify the location and size of drill holes required for component leads and vias (plated through-holes).
Pick and Place Files: Used in surface mount technology (SMT) assembly, these files define the location and orientation for placing electronic components onto the PCB.
Categories: PCBA Manufacturing
Capacitance
Capacitance refers to the ability of a passive electronic component called a capacitor to store electrical energy. Capacitors are essential components within electronic circuits, and understanding their capacitance value is crucial for proper PCB design and functionality. Capacitance is measured in farads (F), picofarads (pF), or microfarads (µF).
Categories: PCBA Manufacturing
Capture
In the realm of electronics and PCB design, capture specifically refers to schematic capture. This is the process of electronically creating a schematic diagram using computer-aided design (CAD) software.
A schematic diagram is a visual representation of an electronic circuit. It uses symbols to depict the electronic components (resistors, capacitors, transistors, etc.) and their interconnections using lines. Schematic capture software offers libraries containing these symbols, allowing efficient and standardized schematic creation.
Categories: PCBA Manufacturing
Chamfer
A chamfer refers to a specific modification made to the edges of a printed circuit board (PCB). It involves cutting or grinding away a small portion of the edge at an angled plane, typically 45 degrees, resulting in a beveled edge instead of a sharp corner. Chamfering reduces risk of damage to sharp corners, allows for easier handling and placement of components during assembly, and may provide a more polished, finished look to the PCB assembly.
Categories: PCBA Manufacturing
Characteristic Impedance
Characteristic impedance (Zo) is a critical concept for ensuring reliable signal transmission on high-frequency PCBs. It represents the inherent resistance of a transmission line (like a trace on a PCB) to oppose the flow of an alternating current (AC) signal. If you compare this transmission line to a garden hose, the characteristic impedance acts like the hose’s width and material properties, affecting how easily and consistently flow (electrical current) moves through it. Wider traces generally have lower Zo.
Categories: PCBA Manufacturing
Check Plots
In the context of PCB manufacturing, check plots are preliminary visual representations of the PCB design used for verification purposes before actual fabrication begins. They are essentially a type of printout that depicts the various layers of the PCB layout.
Categories: PCBA Manufacturing
CIM . Computer-Integrated Manufacturing
In the world of PCB assembly, CIM refers to a paperless manufacturing information system that utilizes computer networks and databases to manage the entire assembly process. It essentially integrates various functionalities under a single computer-controlled system, aiming to improve efficiency, quality, and production output.
Categories: PCBA Manufacturing
Circuit Diagram
A circuit diagram is a graphical representation of an electrical circuit. It shows the components of the circuit and how they are connected using standardized symbols. Circuit diagrams are used for a variety of purposes, including designing, troubleshooting, and repairing electrical circuits. PCB manufacturing typically uses schematic diagrams using standardized symbols to represent the electrical components in the circuit.
Categories: PCBA Manufacturing
Clad
In the context of PCB manufacturing, "clad" refers to a material that is bonded to a base material to create a laminate. This laminate then serves as the foundation for printed circuit boards (PCBs).
Categories: PCBA Manufacturing
Cleanroom
A cleanroom is a meticulously controlled environment designed to minimize airborne contaminants like dust, microbes, and even vaporized particles. Cleanliness requirements can vary depending on the application. Common classifications include ISO 5 (used for sensitive components like high-end processors), ISO 7 (widely used for general PCBA assembly and testing), and ISO 8 (less stringent and suitable for less sensitive applications.) By minimizing contamination, cleanrooms prevent particle-induced defects.
Categories: PCBA Manufacturing
Clearances
Clearances refer to the minimum distances maintained between various elements on a PCB to ensure proper functionality, manufacturability, and prevent electrical shorts. Clearances may be trace-to-trace or trace-to-pad.
Categories: PCBA Manufacturing
Clock
The term "clock" refers to a crucial signal that provides a synchronized timing reference for digital circuits on the PCB. It's essentially a periodic electrical signal with a specific frequency (measured in Hertz, Hz) that dictates the speed of data processing within the circuit. A stable and accurate clock signal synchronizes the flow of digital data within the circuit and determines the speed of circuit operation.
Categories: PCBA Manufacturing
Component Library
A component library is an essential resource in PCB design software. It serves as a centralized repository that stores information and specifications for electronic components commonly used in creating electronic circuits.
What a Component Library Typically Includes:
Symbols: These are graphical representations of the components used in schematics. They depict the component's function using a standardized symbol (e.g., resistor symbol, capacitor symbol, transistor symbol).
Footprints: Footprints define the physical layout of the component on the PCB, including pad sizes, shapes, and pin spacing. This information is crucial for ensuring the component can be correctly soldered onto the board.
Datasheets: While not always directly stored within the library itself, datasheets are often linked or referenced within the component information. Datasheets provide detailed specifications and technical information about the component's performance, electrical characteristics, and recommended usage.
Categories: PCBA Manufacturing
Component Side
The component side refers to the top surface of the PCB where electronic components are typically mounted. It's also sometimes referred to as the assembly side or the top side.
There are a few reasons why components are traditionally placed on the top side of the PCB:
Accessibility: The top side is generally easier to access during the assembly process, allowing for efficient placement and soldering of components.
Inspection and rework: Having components on top facilitates visual inspection for proper placement and soldering quality. Rework or troubleshooting, if necessary, becomes more manageable.
Soldering Techniques: Through-hole components, with leads that pass through holes in the PCB, are often soldered from the bottom side of the board. However, the component leads are typically bent over and clinched onto the pads on the top side for better connection and stability during soldering.
Keep in mind that double-sided PCB assemblies have components mounted on both the top (component side) and bottom side, while multilayer PCBs contain copper traces for routing signals even when components are mounted on both sides.
Categories: PCBA Manufacturing
Conflict Minerals
Conflict minerals are minerals typically mined in war-torn regions or under brutal conditions that fund armed conflict, human rights abuses, and environmental devastation. They can be used within many PCB assemblies as raw materials for components.
Here’s what companies using PCBAs need to know about Conflict Minerals:
- Types of Conflict Minerals: Tantalum, Tin, Tungsten, and Gold (often referred to as 3TG) are the most commonly identified conflict minerals.
- Regulations: The Dodd-Frank Wall Street Reform and Consumer Protection Act (US) and the European Union Conflict Minerals Regulation are key regulations that require companies to identify and mitigate the use of conflict minerals in their products.
- Due Diligence: PCBA contract manufacturers implement due diligence practices to trace the origin of minerals used in their components and ensure they are not sourced from conflict zones. This can involve working with suppliers who are certified conflict-free.
- Benefits of Responsible Sourcing: By taking steps to avoid conflict minerals, companies can:
- Uphold ethical sourcing practices.
- Mitigate reputational risk.
- Comply with regulations.
- Attract customers who value responsible sourcing.
Categories: PCBA Manufacturing
Conformal Coating
Conformal coating is a thin polymeric film applied to printed circuit boards (PCBs) to provide a protective layer against various environmental threats. It acts as a barrier, safeguarding the delicate electronic components and circuitry from:
Moisture: Conformal coatings prevent moisture ingress, which can lead to electrical shorts, corrosion, and ultimately, circuit failure. This is especially crucial for PCBs used in humid environments or applications exposed to water or condensation.
Dust and Contaminants: The coating creates a barrier against dust, dirt, and other airborne contaminants that could cause electrical shorts or malfunction.
Corrosion: Conformal coatings can help protect components from corrosive materials or harsh chemicals that might be present in the operating environment.
Thermal Shock: Certain coatings can offer some degree of protection against rapid temperature changes, which can cause stress on components and solder joints.
Abrasion: A thin layer of coating can provide some level of protection against minor physical wear and tear.
Categories: PCBA Manufacturing
Connection
Connection refers to the means by which electrical components are joined together to create a functioning circuit. These connections allow for the flow of electricity between components, enabling them to operate and interact as intended. Connections can be made via soldering, crimping, wire wrapping, or press-fitting.
Categories: PCBA Manufacturing
Connectivity
Connectivity refers to the ability of devices, systems, or components to establish connections and communicate with each other. This communication can involve exchanging data, transmitting signals, or sharing resources. Connectivity is a fundamental concept that underpins the operation of modern electronic devices and networks.
Categories: PCBA Manufacturing
Contract Manufacturer
A contract manufacturer (CM) is a company that specializes in the production of printed circuit board assemblies (PCBAs) on behalf of other companies. CMs provide a comprehensive range of services, including:
PCB Design Review: Reviewing and potentially optimizing the PCB design for manufacturability and functionality.
Procurement: Sourcing and acquiring all the necessary electronic components for the PCB assembly.
PCB Fabrication: Manufacturing the bare PCBs based on the design specifications.
PCB Assembly: Populating the PCBs with electronic components using soldering, crimping, or other connection methods.
Testing: Performing various electrical and functional tests to ensure the PCBs meet the required specifications.
Quality Control: Implementing quality control procedures throughout the manufacturing process to ensure consistent and reliable PCB assemblies.
Categories: PCBA Manufacturing
Controlled Dielectric
Controlled Dielectric is a PCB design technique involving selecting materials with controlled dielectric constants (Dk) for each layer of the stack-up. The PCB designer specifies the target Dk value, dielectric loss tangent (Df) (if critical), product name (material designation), and thickness for each layer material. The designer performs the impedance and trace width calculations. The CM follows the designer's specifications. They source laminates with the requested properties and ensure they work with their fabrication processes. This design technique is for PCB designs where precise Dk control is key. It is often used as a foundation for controlled impedance design.
Categories: PCBA Manufacturing
Controlled Impedance Design
Controlled Impedance Design is a PCB design technique focused on achieving a predetermined impedance profile for each layer in the stack-up. The PCB designer provides the target impedance profile for each layer. The CM plays a more active role in material selection. They use their expertise to choose laminates with appropriate Dk values. They also determine optimal layer thicknesses and trace widths to achieve the target impedance profile provided by the designer. Effective communication between the two parties is key here.
Categories: PCBA Manufacturing
Copper Pour
A copper pour refers to a large, continuous area of copper on a PCB layer that is not used for signal routing. These pours are typically used for several important functions including:
Grounding and Power Distribution: Copper pours can be used to create ground and power planes.
Heat Dissipation: Copper has good thermal conductivity. Large areas of copper can help spread and dissipate heat from components.
Electromagnetic Interference (EMI) Shielding: Large copper pours can act as a shield, attenuating unwanted electromagnetic emissions from the PCB and reducing susceptibility to external EMI.
Categories: PCBA Manufacturing
Copper Weight
Copper weight refers to the thickness of the copper foil laminated onto a base material in a PCB layer. It is measured in ounces per square foot (oz/ft²) for imperial units or micrometers (µm) for metric units. The appropriate copper weight selection is critical for several factors:
Current Carrying Capacity: Thicker copper offers a larger cross-sectional area, allowing it to carry higher currents without overheating.
Signal Integrity: Copper weight can influence signal integrity, particularly for high-frequency applications. Thicker copper reduces signal attenuation and improves signal quality.
Board Weight and Manufacturability: Heavier copper translates to a heavier PCB.
Categories: PCBA Manufacturing
Core
A core is the central insulating material that forms the rigid base structure of the PCB. It is typically made from a layered composite material with high electrical insulating properties and mechanical strength. Core selection is crucial for meeting electrical, mechanical, and thermal requirements in PCB design. Contract manufacturers leverage their material expertise to recommend suitable cores, collaborate on stack-up design, and ensure process compatibility to support precise manufacturing outcomes.
Categories: PCBA Manufacturing
Core Thickness
Core thickness refers to the thickness of the core material used in multilayer PCBAs. It directly affects signal speed and impedance. Thicker cores slow signals and raise impedance. They also make routing harder and increase manufacturing costs.
Categories: PCBA Manufacturing
Counterbore
A counterbore is a cylindrical hole with a flat bottom machined into the PCB substrate. It is typically used to create a recess for the head of a screw or nut, allowing the fastener to sit flush with the PCB surface.
Categories: PCBA Manufacturing
Countersink
A countersink is a cone-shaped hole machined into the PCB substrate. It is typically used to create a recess for the tapered head of a countersunk screw. The screw head sits below the PCB surface when tightened, creating a smooth and streamlined finish.
Categories: PCBA Manufacturing
Coupling
Coupling refers to electrical/magnetic interaction between conductive traces or components on a PCBA that can cause signal interference known as crosstalk. This phenomenon primarily manifests in two forms: capacitive coupling and inductive coupling. Capacitive coupling happens when changes in voltage on one trace affect another due to the capacitance between them. Inductive coupling occurs when a changing current in one trace induces a voltage in another. Both can degrade the signal's integrity on a PCBA.
Categories: PCBA Manufacturing
Coupon
See test coupon
A coupon is a small, representative sample piece of the PCBA that is used for testing and quality control. Coupons are typically located on the edges of the PCBA panel and include various features like traces, vias, pads, and other elements that mimic the actual board's design. They are used to test parameters such as layer alignment, solderability, electrical continuity, and impedance. Coupons help ensure that the PCBA meets the required specifications and standards before the entire batch goes into full production.
Learn more about testing electronics circuit boards now.
Categories: PCBA Manufacturing
Crosshatching
Crosshatching refers to a technique where large copper planes within a Printed Circuit Board (PCB) are intentionally broken up or etched away to form a pattern of intersecting lines, resembling a mesh or lattice.
Flex and Rigid-Flex PCBs: Crosshatching is primarily used in flexible and rigid-flex PCBs. It enhances flexibility while maintaining electrical functionality. By removing a controlled amount of copper, the design allows the board to bend without compromising trace integrity or ground plane performance.
Reduced Electromagnetic Interference (EMI): A solid copper plane can act like an antenna, capturing and radiating electromagnetic interference. The grid-like structure of crosshatching disrupts this effect, helping to minimize EMI issues.
Thermal Management: Crosshatching helps reduce the thermal mass of copper planes, improving heat dissipation. This can be crucial in high-temperature applications or in designs where components generate significant heat.
Categories: PCBA Manufacturing
Crosstalk
Crosstalk is an undesirable electrical phenomenon that occurs on PCBAs when electromagnetic interference (EMI) from a nearby signal trace couples (or "talks") to another trace. This interference typically occurs because of capacitive or inductive coupling between signal paths that are in close proximity. This unwanted coupling can distort the intended signal on the receiving trace, potentially leading to data errors or malfunctions in the circuit.
Categories: PCBA Manufacturing
CTE, Coefficient of Thermal Expansion
The Coefficient of Thermal Expansion (CTE) is a material property that describes how much a material will change in size (expand or contract) with a change in temperature. CTE is a critical factor when considering the different materials used in a board, such as the copper foil, laminate substrate, and solder. A well-matched CTE among the PCB materials is key. It stops delamination, warping, and solder joint failures. This ensures the reliability and longevity of the assembly in changing thermal conditions.
Categories: PCBA Manufacturing
Current
Current refers to the flow of electrical charge through a conductor. It is typically measured in amperes (Amps). The current rating of a PCB trace or component determines its capacity to handle electrical load without overheating or failing.
Categories: PCBA Manufacturing
Curing
Curing refers to a chemical process used in PCB manufacturing to solidify and harden photosensitive materials like solder mask and legend ink. This process typically involves exposure to heat, ultraviolet light, or a combination of both, depending on the specific material used.
Categories: PCBA Manufacturing
Cut-Tape
Cut-tape components are electronic components supplied on reels of tape that have been pre-separated into individual units. This format allows for automated pick-and-place machines to accurately pick and place the components onto a PCB during the assembly process. Thus, cut-tape components are ideal for high-volume PCB assembly. They help achieve faster assembly times and lower production costs for contract manufacturers.
Categories: PCBA Manufacturing
Date Code
A date code is a unique identifier printed on a PCB that indicates the manufacturing date or batch. The format of the date code can vary depending on the manufacturer, but it typically consists of a combination of numbers and letters representing the week and year of production.
Importance of Date Codes:
Traceability: Date codes help trace the manufacturing history of a PCB. In the event of a defect or failure, the date code allows manufacturers to identify when and potentially where the board was produced, aiding in root cause analysis and corrective actions.
Quality Control: By tracking date codes, manufacturers can monitor and control the quality of different production batches. If a particular batch has quality issues, date codes can help isolate and address the problem quickly.
Inventory Management: Date codes facilitate efficient inventory management by helping companies manage stock based on the age of the components. This is particularly important for components with a limited shelf life.
Warranty and Service: Date codes verify if a PCB is under warranty and guide service actions based on its manufacturing date.
Categories: PCBA Manufacturing
Delamination
Delamination is the separation of layers within a PCB. It occurs when the adhesive bond between the laminate layers fails, causing the board to split apart. It can lead to mechanical failure and electrical performance issues, making the PCB unusable.
Delamination can be caused by various factors, including:
Poor Laminate Quality: Inferior quality materials or manufacturing defects in the laminate (the insulating material between copper layers) can predispose a PCB to delamination.
Moisture Absorption: Certain PCB materials can absorb moisture over time, which can weaken the adhesive bond and contribute to delamination.
Mechanical Stress: Excessive bending, twisting, or impact during handling or assembly can cause physical damage, leading to delamination.
Improper Manufacturing Processes: Incorrect processing parameters during PCB fabrication, such as inadequate curing of the laminate, improper layer alignment, or inadequate bonding pressure, can result in weak interlayer adhesion.
To detect delamination, inspect visually, use X-ray, perform ultrasonic testing, and analyze cross-sections. To prevent delamination, choose materials wisely, store them properly, control processing, consider the design thoughtfully, and handle and assemble carefully.
Categories: PCBA Manufacturing
Desoldering
Desoldering refers to the controlled removal of solder and electronic components from a Printed Circuit Board (PCB). This process is typically required for various purposes in PCBA manufacturing, including rework, repair, and component replacement.
Various methods, including desoldering wick, desoldering pumps, hot air rework stations, and desoldering irons, are used based on the specific needs of the task. Best practices include proper preparation, even heating, gentle component removal, and thorough post-desoldering cleaning.
Categories: PCBA Manufacturing
Destructive Testing
Destructive testing plays a crucial role in evaluating the quality, reliability, and performance of assembled PCBs. Unlike non-destructive testing methods, which don't harm the board, destructive testing involves stressing the PCB to the point of failure to assess its characteristics. This may include thermal stress testing, mechanical stress testing, electrical stress testing, and failure analysis.
Categories: PCBA Manufacturing
DFM, Design for Manufacturing
Design for Manufacturability (DFM) is a fundamental concept in PCB (Printed Circuit Board) design. It emphasizes incorporating manufacturability considerations throughout the design process. By prioritizing good electronic design and manufacturability, designers can create PCBs that are:
Efficient to Produce: DFM principles lead to efficient manufacturing processes, reducing production time and associated costs.
Cost-Effective: By optimizing for manufacturability, DFM helps minimize material waste, reduce rework, and improve overall yield, leading to cost-effective production.
High-Quality and Reliable: PCBs designed with DFM in mind are less prone to manufacturing defects, resulting in higher quality and more reliable end products.
Categories: PCBA Manufacturing
DF, Dissipation Factor
The Dissipation Factor is a dimensionless quantity that represents the ratio of the power dissipated (lost) in an insulating material to the power stored in the electric field. It indicates the extent to which a dielectric material (insulator) converts electrical energy into heat. It measures the inefficiency of an insulating material to store electrical energy and is critical for evaluating the performance of PCBs, especially in high-frequency applications.
Categories: PCBA Manufacturing
Die Bonding
Die bonding is the process of securing a semiconductor die to a substrate. This step is essential in the manufacturing of microelectronic devices, ensuring the die is firmly attached and capable of maintaining electrical and thermal connections throughout the device’s lifecycle. Proper material selection, process control, cleanliness, and inspection are critical for achieving high-quality die bonds.
Categories: PCBA Manufacturing
Dielectric Constant
The dielectric constant, also sometimes referred to as the relative permittivity (εr), is a material property that quantifies its ability to store electrical energy when placed in an electric field. In simpler terms, it tells you how much more efficiently a material can store electrical energy compared to a vacuum. The dielectric constant is affected by a variety of factors such as the composition of the material, the temperature, and the frequency.
Categories: PCBA Manufacturing
Differential Signaling
Differential signaling is a method for transmitting electrical data using two complementary voltage signals. These signals, often referred to as a differential pair, carry equal and opposite logic values. This technique offers several advantages over traditional single-ended signaling, particularly in high-speed applications.
In differential signaling, the data is encoded in the voltage difference between a balanced pair of signals, making it less susceptible to external noise. Differential signaling offers superior noise immunity, reduced EMI emissions, and allows for higher data rates by leveraging common-mode noise cancellation. This method is often used in computer buses like USB and DDR memory interfaces, networking standards like Gigabit Ethernet, and high-speed interconnects.
Categories: PCBA Manufacturing
Dimensional Stability
Dimensional stability refers to a PCB's ability to maintain its intended size and shape throughout various environmental conditions and manufacturing processes. This property is crucial because variations in the size or shape of the PCB can lead to misalignment of components, poor solder joint reliability, and potential failure of the board in its application.
Factors Affecting Dimensional Stability:
Material Properties: The thermal expansion coefficient (CTE) of the PCB materials significantly impacts dimensional stability. Materials with mismatched CTEs can cause warping or delamination during thermal cycling.
Moisture Absorption: Certain PCB materials, like FR-4, can absorb moisture from the environment, leading to dimensional changes.
Manufacturing Processes: High temperatures and pressures used during lamination and drilling can induce slight dimensional variations.
To improve dimensional stability, choose materials with matching CTEs. It also helps to use a balanced layer stack-up with an even distribution of copper. To keep moisture out and further protect the board, consider adding a solder mask or conformal coating.
Categories: PCBA Manufacturing
Dimple
Dimples are small depressions or indentations found on the surface of a PCBA. They can be either intentional, resulting from specific manufacturing processes, or unintentional, caused by defects or irregularities during production. While they might seem minor, they can significantly impact the electrical and mechanical performance of a PCB. Preventing dimples involves stringent process control, quality assurance, and careful material selection.
Causes of Dimples:
Soldering Process: During the soldering process, especially in wave soldering or reflow soldering, dimples can form due to the cooling and solidification of the solder. If the solder cools unevenly or if there are variations in the solder paste application, dimples can appear.
Drilling and Plating: When vias (small holes that connect different layers of the PCB) are drilled and subsequently plated with copper, dimples can form if there are inconsistencies in the plating process. This can be due to improper cleaning, inadequate plating thickness, or uneven application of materials.
Material Defects: Variations in the PCB substrate material or the copper foil can lead to dimples. These material defects might be inherent from the raw materials or arise during handling and storage.
Categories: PCBA Manufacturing
Direct Coupling
Direct coupling refers to the technique of connecting two circuit stages using a conductive path without any additional components like capacitors or transformers. This establishes a direct current (DC) electrical connection between stages. Direct coupling transfers both the AC signals and DC bias signals. Direct coupling offers excellent low-frequency response and allows for a simpler design with fewer components. However, it requires careful design to minimize offset errors.
Categories: PCBA Manufacturing
DNI/DNP Do Not Install/Do Not Populate
DNI (Do Not Install) and DNP (Do Not Populate) are interchangeable terms used in PCB assembly documentation to indicate that specific components should not be installed on the final printed circuit board (PCB).
Categories: PCBA Manufacturing
DRC, Design Rule Check
Design Rule Check (DRC) is a critical step in the PCB design process. It's an automated verification process that ensures the PCB layout complies with a predefined set of design rules established by the PCB manufacturer. These rules govern various aspects of the PCB layout, such as:
Minimum trace width and spacing: This ensures sufficient space between conductive traces to prevent electrical shorts during fabrication.
Annular ring width: This defines the width of the copper ring surrounding the drilled hole for component leads.
Solder joint clearances: This ensures proper solder joint formation during assembly.
Via types and placements: This verifies the types of vias used (plated through-hole, buried via, etc.) and their placement within the PCB layers.
Minimum drill hole size: This ensures reliable drilling and plating of holes for component leads.
By catching potential layout violations early, Design Rule Checks (DRC) significantly reduce fabrication errors, improve yield, and ensure high-quality, manufacturable PCBs.
Categories: PCBA Manufacturing
Drill File
A drill file is a digital file that furnishes crucial instructions for drilling machines used in PCB fabrication. It encodes essential details for each hole drilled on the PCB, including:
Hole location: X and Y coordinates specifying the precise location of each hole on the PCB.
Hole diameter: Defines the exact diameter of each drilled hole to accommodate component leads or vias.
Hole type: Specifies the type of hole required, such as plated through-hole, non-plated through-hole, or buried via.
Drill files help contract manufacturers by ensuring precise drilling, optimizing fabrication processes, and minimizing errors.
Categories: PCBA Manufacturing
DUT, Device Under Test
Device Under Test (DUT) refers to the individual assembled PCB undergoing electrical testing to verify its functionality and conformance to design specifications. This testing can include electrical verification, stress testing, and environmental testing among others.
Categories: PCBA Manufacturing
DUT Testing Process
The DUT is connected to an automated test equipment (ATE) system.
The ATE system executes a predefined test program designed to stimulate the DUT's circuitry and evaluate its response.
Test results are analyzed to identify any electrical faults or deviations from expected behavior.
Categories: PCBA Manufacturing
DVT, Design Validation Test
Design Validation Testing (DVT) is a series of tests conducted on a prototype PCB to verify its functionality, performance, and conformance to the design specifications. It essentially bridges the gap between design and manufacturing by evaluating whether the PCB performs as intended in a real-world setting.
Categories: PCBA Manufacturing
ECIA
The Electronic Components Industry Association (ECIA) is a trade association that represents manufacturers, suppliers, and distributors of electronic components. ECIA develops and maintains standards, provides industry data, and promotes best practices to enhance the efficiency and effectiveness of the electronic components supply chain.
ECIA standards cover various aspects of component packaging, moisture sensitivity, configuration management, and solder paste evaluation. By adhering to these standards and using ECIA resources, industry professionals can enhance the efficiency, quality, and reliability of their PCB designs and assemblies.
Categories: PCBA Manufacturing
ECL, Emitter Coupled Logic
ECL is a bipolar transistor-based logic family known for its exceptional speed. Compared to standard logic circuits like TTL (Transistor-Transistor Logic), ECL can achieve significantly faster operation. This makes it suitable for high-frequency applications. While offering superior speed, ECL comes with some drawbacks:
Cost: ECL circuits can be more expensive to implement compared to simpler logic families due to the complexity of the circuitry.
Power Consumption: ECL circuits typically consume more power than other logic families like CMOS (Complementary Metal-Oxide-Semiconductor).
Design Complexity: Designing with ECL can be more challenging compared to some other logic families.
Categories: PCBA Manufacturing
ECAD, Electronic Computer Aided Design
ECAD stands for Electronic Computer-Aided Design. It refers to software tools used for designing and developing electronic circuits, including those found on Printed Circuit Boards (PCBs). ECAD tools provide features for schematic capture, PCB layout, component libraries, design rule checking, 3D visualization, simulation, and collaboration. These tools help manage the complexity of electronic designs, ensure design integrity, facilitate collaboration, and generate necessary documentation for manufacturing and assembly.
Categories: PCBA Manufacturing
ECN, Engineering Change Notice or ECO, Engineering Change Order
ECN (Engineering Change Notice) and ECO (Engineering Change Order) are essentially interchangeable terms used in the context of PCB design and manufacturing. Both refer to a formal document that proposes a modification to a PCB. This may result from component availability issues, design improvements, or unexpected challenges encountered during fabrication.
Categories: PCBA Manufacturing
Electroplating
Electroplating, also known as electrodeposition, is a process where a metal layer is deposited onto a conductive surface using an electric current. Electroplating is primarily used to deposit metals such as copper, nickel, gold, and tin onto the PCB surface and through-hole walls. This metallic coating serves several important functions:
Enhanced Conductivity: Electroplating improves the electrical conductivity of the PCB by providing a continuous metal layer, which is essential for reliable electrical connections.
Solderability: The plated metal layer enhances the solderability of the PCB, ensuring strong and reliable solder joints during component assembly.
Corrosion Resistance: Electroplating provides a protective layer that prevents oxidation and corrosion, extending the lifespan of the PCB.
Durability: The metal layer adds mechanical strength to the PCB, particularly in through-holes and vias, which are critical for maintaining structural integrity during thermal and mechanical stress.
Categories: PCBA Manufacturing
Embedded
An embedded PCB is a special type of PCB that goes beyond simply reducing the overall size. It achieves miniaturization by incorporating electronic components within the PCB itself, rather than just on the surface. This allows for a significant reduction in the overall footprint of the PCB compared to a traditional design with all components mounted on the surface. PCB assemblies that are embedded integrate passive components within their interior layers through passive technologies such as printing or etching, or by laser drilling and embedding pre-manufactured components into cavities created during fabrication.
PCB assemblies using embedded technologies are typically smaller and have improved performance and increased reliability. Due to the complexity of the design, the fabrication process is typically more complex and expensive.
Categories: PCBA Manufacturing
EMC–Electromagnetic Compatibility
EMC (Electromagnetic Compatibility) refers to a device's ability to operate as intended in an environment filled with electronic equipment without causing interference or being disrupted by it. Imagine an orchestra – each instrument (device) must play its part without throwing off the others (causing interference) and needs to be able to hear its cues clearly (immunity from interference).
EMC is crucial for ensuring the smooth operation of electronics in our increasingly crowded technological world.
Categories: PCBA Manufacturing
Emitter
In a transistor, the emitter is a heavily doped region designed to emit (release) a large number of charged particles, typically electrons in an NPN transistor. These electrons act as the current carriers within the device. The flow of electrons constitutes an electric current.
Categories: PCBA Manufacturing
EMI, Electromagnetic Interference
Electromagnetic Interference (EMI) is the disruption of the operation of an electronic device when it is exposed to an electromagnetic field. EMI can cause degradation in the performance of electronic equipment or complete malfunction.
Managing EMI is essential to ensure the proper functioning of electronic devices and to comply with regulatory standards. Common best practices for EMI management include:
Shielding: Enclosing sensitive circuits in metallic enclosures or using shielded cables can protect against external EMI. Shielding can also prevent internal components from radiating EMI.
PCB Layout Techniques: Careful PCB layout design can minimize EMI. This includes strategies like separating high-speed and low-speed circuits, minimizing loop areas, and using ground planes.
Twisted Pair and Differential Signaling: Using twisted pair cables and differential signaling reduces susceptibility to EMI by canceling out noise that affects both lines equally.
Decoupling Capacitors: Placing decoupling capacitors near power pins of ICs helps to filter out high-frequency noise and stabilize power supply voltages.
Filtering: Using filters, such as ferrite beads, capacitors, and inductors, can attenuate EMI by blocking high-frequency noise from entering or leaving the circuit.
Categories: PCBA Manufacturing
EMP, Electromagnetic Pulse
An EMP (Electromagnetic Pulse) is a short-duration, broadband electromagnetic radiation transient induced by a rapid change in the surrounding electromagnetic field. This rapid change can couple with conductive structures, inducing high voltage and current surges that disrupt or damage electronic circuitry.
Categories: PCBA Manufacturing
EMR, Electromagnetic Radiation
Electromagnetic Radiation consists of waves of electric and magnetic fields that propagate through space. EMR covers a broad spectrum, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. EMR can affect signal integrity, cause electromagnetic interference (EMI), and pose challenges for regulatory compliance and health safety. Adherence to regulatory standards ensures that electronic devices meet required EMR performance criteria, preventing interference with other devices and ensuring safe operation.
Sources of EMR in PCBAs
High-Frequency Components: Components such as oscillators, processors, and RF modules generate EMR as part of their operation.
Switching Power Supplies: Rapid switching in power supplies can produce significant EMR.
High-Speed Digital Circuits: Fast digital signals, particularly in high-speed communication and processing circuits, can radiate EMR.
Managing EMR involves strategies such as shielding, using ground planes, proper trace routing, component placement, filtering, differential signaling, and impedance control.
Categories: PCBA Manufacturing
EMS, Electronics Manufacturing Service
EMS (Electronics Manufacturing Services) companies are behind-the-scenes partners that help bring electronic devices to life. They specialize in taking care of the entire, or part of, the Printed Circuit Board Assembly (PCBA) process for other companies, including some or all of the following:
Fabrication: This involves creating the bare PCB according to the design specifications.
Assembly: EMS companies place electronic components onto the PCB and solder them in place.
Testing: They ensure the assembled PCB functions correctly through various electrical tests.
Benefits of using EMS companies include reduced costs, quality control, and the benefits of expertise and efficiency.
Categories: PCBA Manufacturing
End-to-End Design
End-to-end design in PCBA manufacturing encompasses the entire process of bringing a printed circuit board assembly (PCBA) to life, from the initial concept to the final tested product. It involves several key stages:
Design & Development: Electronic design software (EDA) is used to create the circuit schematic and PCB layout, along with a Bill of Materials (BOM) listing all required components.
PCB Fabrication: Gerber files derived from the PCB design are used by the manufacturer to build the bare PCBs based on specifications.
PCBA Assembly: Components are procured, placed on the PCB with solder paste, soldered, cleaned, inspected, and tested for functionality.
Programming and Testing: Programmable components are loaded with software and the entire PCBA undergoes functional testing to ensure it operates as designed.
Quality Control:Quality control measures are implemented throughout the entire process to guarantee consistent, defect-free PCBAs.
Categories: PCBA Manufacturing
ENIG
ENIG (Electroless Nickel Immersion Gold) is a widely used two-layer surface furnish applied to the copper surfaces of a PCB finish for PCBs. The process involves depositing a layer of nickel via an electroless plating method, followed by a thin layer of gold through an immersion process. The gold layer protects the nickel from oxidation and provides a good surface for soldering and wire bonding.
While it is more expensive and complex than some other finishes, its advantages include:
Flat Surface: ENIG provides a very flat surface, which is beneficial for the assembly of surface-mount devices (SMDs) and fine-pitch components.
Excellent Solderability: The gold layer ensures excellent solderability, making the assembly process easier and more reliable.
Corrosion Resistance: The nickel layer provides a barrier to copper diffusion, and the gold layer protects the nickel from oxidation and corrosion.
-Durability: ENIG is durable and resistant to environmental factors, making it suitable for use in harsh conditions.
- Compatibility with Lead-Free Soldering: ENIG is compatible with lead-free soldering processes, making it suitable for use in RoHS-compliant applications.
Categories: PCBA Manufacturing
ENEPIG
ENEPIG ( Electroless Nickel Electroless Palladium Immersion Gold) is a type of surface furnish that involves the deposition of three layers of metal on the PCB's copper surface: a layer of electroless nickel, followed by a layer of electroless palladium, and finally a thin layer of immersion gold.
While ENEPIG is more expensive and complex than other finishes, its advantages make it suitable for high-reliability applications, high-frequency circuits, and wire bonding.
Advantages of ENEPIG
Improved Solderability: The gold layer ensures excellent solderability, and the palladium layer enhances wetting, resulting in strong and reliable solder joints.
Corrosion Resistance: The palladium layer provides an additional barrier against corrosion, protecting the nickel layer from oxidation.
Wire Bonding: ENEPIG is suitable for both gold and aluminum wire bonding, making it versatile for various applications.
Compatibility with Lead-Free Soldering: ENEPIG is compatible with lead-free soldering processes, making it suitable for RoHS-compliant applications.
Reduced Black Pad Risk: The palladium layer helps mitigate the black pad phenomenon, a type of corrosion that can occur at the nickel-gold interface in ENIG finishes.
Enhanced Durability: The combination of nickel, palladium, and gold layers provides excellent mechanical and thermal durability, ensuring long-term reliability.
Read a comparison of Enig vs Enepig surface finishes now.
Categories: PCBA Manufacturing
ERAI, Electronics Resellers Association International
In the broader electronics industry, ERAI stands for the Electronic Resellers Association International. Founded in 1995 as the Electronic Resellers Association (ERA), it later expanded its focus and membership base. The ERAI provides supply chain risk mitigation solutions and resources, maintains a comprehensive database of reported counterfeit components and high-risk suppliers, and educates members about mitigating counterfeit risks.
Categories: PCBA Manufacturing
ERP, Enterprise Resource Planning
ERP (Enterprise Resource Planning) is a comprehensive software suite integrating core business processes. It encompasses modules like MRP (optimizing production), SCM (managing supply chain), CRM (handling customers), financials (accounting & budgeting), and HCM (managing employees). By utilizing a central database, ERP fosters real-time data sharing and boosts operational efficiency across an organization.
Categories: PCBA Manufacturing
Engineering Sample
An Engineering Sample (ES) is a pre-production version of a Printed Circuit Board Assembly (PCBA) built for internal testing, validation, and demonstration purposes. ES units are crucial stepping stones between the design phase and mass production. Engineering samples save time and money by catching design flaws early by validating the function of the PCBA before mass production, allowing for design improvements.
Categories: PCBA Manufacturing
ESD, Electrostatic Discharge
Electrostatic Discharge (ESD) refers to the sudden, unwanted flow of electric current between two objects at different electrical potentials. This rapid discharge of static electricity can damage sensitive electronic components on PCBs during handling, assembly, or even everyday use. ESD is a leading cause of electronic component failures and can lead to costly rework or scrapped PCBAs. Taking proper control measures ensures product quality and reliability.
Categories: PCBA Manufacturing
Etching
Etching is the process of removing excess copper from a PCB substrate, leaving behind the desired copper traces, pads, and other features that form the circuit. The etching process follows the application of a photoresist or etch resist, which protects the areas of copper that should remain.
Categories: PCBA Manufacturing
FA, First Article
A First Article (FA) represents the very first complete PCB assembly produced using the finalized mass production process. It's a critical milestone that ensures everything is functioning smoothly before full-scale manufacturing kicks off. First articles verify the manufacturability of the PCBA design with the chosen processes, identifies any potential production issues, and provides a baseline for future quality control inspections.
Categories: PCBA Manufacturing
Fab
See Fabrication or Fab House
Categories: PCBA Manufacturing
Fab House
A Fab House, short for Fabrication House, is a company specializing in the creation of bare printed circuit boards (PCBs). These facilities act as the cornerstone for PCB production, transforming electronic designs into a physical reality.
Categories: PCBA Manufacturing
Fabrication
Fabrication (Fab) refers to the process of creating the bare printed circuit board (PCB). This stage involves transforming a design layout into a physical board with conductive traces, pads, and other features. During fabrication, the design layout is transferred onto photosensitive film, which is then used to create a resist pattern on the copper layer of the PCB. Unwanted copper is etched away, leaving behind desired conductive traces and pads. Then holes are drilled for component leads and vias. Finally, the PCB is plated with finishes like gold or nickel for better conductivity and corrosion resistance.
Categories: PCBA Manufacturing
FAI, First Article Inspection
First Article Inspection (FAI) is a critical quality control procedure conducted during the initial stages of PCBA production. It involves a thorough examination of a sample of the first manufactured PCBs to verify their compliance with the design specifications and manufacturing requirements.
FAI ensures quality by checking the first product, validates production processes, reduces costs by catching problems early, and helps meet regulations and customer expectations. This all leads to increased customer confidence in the products.
Best practices for FAI include clear communication, comprehensive documentation, use of checklists, training and competence, continuous improvement, and customer involvement. Conducting a thorough FAI is essential for preventing defects and ensuring the consistent production of high-quality PCBs.
Categories: PCBA Manufacturing
Farad
Farad (F) is the unit of electrical capacitance in the International System of Units (SI). Capacitance represents the ability of a component to store electrical charge.
Categories: PCBA Manufacturing
FCT, Functional Test
Within PCBA manufacturing, a Functional Test (FCT) serves as a crucial quality check to verify the overall functionality of the assembled PCB. It goes beyond basic electrical testing and simulates real-world operating conditions. Functional testing typically includes testing power supplies and voltage levels, verifying signal integrity between components, checking the functionality of input/output ports and other communication interfaces, and running diagnostic software to identify potential issues.
Categories: PCBA Manufacturing
Ferrite
Ferrites are magnetic materials that exhibit high magnetic permeability and low electrical conductivity. They are used to control electromagnetic interference by absorbing and dissipating high-frequency noise in electronic circuits. Ferrites in PCBAs improve EMI performance, enhance signal integrity, and boost circuit stability.
Common Applications of Ferrites in PCBA Design
EMI Suppression: Ferrites exhibit an impedance that increases with frequency. This allows them to act as a filter, attenuating high-frequency noise currents that may travel on power and signal lines.
Power Plane Decoupling: Ferrite beads and cores are used on power supply lines to filter out switching noise from power converters and ensure clean power is delivered to sensitive components.
Categories: PCBA Manufacturing
Fine Line
Fine Line refers to the minimum width and spacing achievable for conductive traces and features on a PCB. As electronic components continue to shrink and functionalities increase, the demand for finer lines on PCBs grows. This allows for:
Higher Density Interconnects (HDI): Packing more components and functionalities onto a smaller PCB footprint. This trend is particularly relevant in miniaturized devices like smartphones and wearables.
Improved Signal Integrity: Fine lines can minimize signal propagation delays and crosstalk between closely spaced traces, leading to better signal quality and performance.
Categories: PCBA Manufacturing
Fine Pitch
Fine Pitch refers to the spacing between the leads or balls on a component. This spacing is typically measured in millimeters (mm) or micrometers (µm), with finer pitches indicating smaller component sizes. Due to their small size, fine pitch components require high-precision placement and soldering techniques.
Categories: PCBA Manufacturing
Finished Copper
Finished Copper refers to the final thickness of the copper layer(s) on a PCB after all fabrication processes are complete. It's a crucial parameter that impacts several aspects of the PCB's functionality and performance.
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Firmware
Firmware is a set of permanent instructions that program the behavior of a specific hardware device such as microcontrollers or programmable logic devices (PLDs) on the PCBA.
Categories: PCBA Manufacturing
Flash
In PCBA manufacturing, "Flash" refers to non-volatile memory chips, typically Flash memory, embedded onto the PCB. This type of memory retains data even when the PCBA loses power, making it ideal for storing programs, firmware, and critical configuration settings. Flash memory can be programmed and erased electronically, allowing for in-field updates or data logging capabilities.
Categories: PCBA Manufacturing
Flow Soldering
Flow Soldering is a high-volume soldering process used to efficiently join electronic components to printed circuit boards (PCBs). It involves a continuous wave of molten solder through which the PCBs are passed.
Advantages of flow soldering include efficiency, consistency, cost-effectiveness, and reliability. Best practices involve proper flux application, optimized preheating, careful adjustment of wave solder parameters, correct component placement, post-solder cleaning, and regular equipment maintenance.
Categories: PCBA Manufacturing
FMEA
FMEA (Failure Mode and Effects Analysis) is a proactive, systematic approach used to identify, assess, and prioritize potential failure modes within a process or product. FMEA involves a detailed analysis of possible failure modes, their effects, causes, and existing controls, followed by calculating a Risk Priority Number (RPN) to prioritize actions.
In PCBA manufacturing, FMEA plays a crucial role in:
Proactive Risk Management: Identifying potential failure modes in the PCB assembly process allows for preventive measures to be implemented, minimizing the risk of defects or malfunctions in the final product.
Process Optimization: By analyzing the potential consequences of failures, FMEA helps identify areas for improvement in the PCB assembly process, leading to higher production quality and yield.
Cost Reduction: Preventing defects through FMEA can significantly reduce the costs associated with rework, scrap, and warranty claims.
Categories: PCBA Manufacturing
Footprint
"Footprint" refers to the physical space occupied by a component on the PCB layout. It's essentially the outline or "shadow" of the component, including its leads or pins. Footprint size is a crucial factor when optimizing space utilization on a PCB assembly, especially for densely populated boards.
Categories: PCBA Manufacturing
Forward Bias
Forward Bias is a term used in semiconductor physics to describe the condition when a positive voltage is applied to the p-side of a p-n junction diode relative to the n-side, allowing current to flow through the diode.
Read more about biasing of a diode now.
Categories: PCBA Manufacturing
Frequency Modulation
Frequency Modulation is a technique used to transmit information by varying the frequency of a carrier wave. It's a fundamental concept in wireless communication systems like radio and television.
Categories: PCBA Manufacturing
Functional Test
Functional testing is the process of testing a PCB to ensure that all components and circuits perform their intended functions correctly. Unlike other testing methods that might focus on specific aspects (such as electrical connectivity or component placement), functional testing evaluates the PCB as a whole, in a manner similar to how it will be used in its final application.
Functional testing ensures quality assurance, detects defects, and saves costs by addressing issues early. Best practices include comprehensive planning, automated testing, early testing, clear criteria, environmental considerations, continuous improvement, and cross-functional collaboration.
Categories: PCBA Manufacturing
Gerber File
A Gerber file is the industry standard format for conveying PCB design data to fabrication houses. It acts as a digital blueprint, meticulously detailing every aspect of the PCB layout for accurate manufacturing. Gerber files ensure a universal and standardized way to communicate PCB design data between designers and manufacturers to enable accurate PCB assembly and fabrication.
Categories: PCBA Manufacturing
GPS, Global Positioning System
GPS is a satellite-based navigation system that uses a network of satellites to provide precise location, velocity, and time information to a GPS receiver located on Earth. It consists of three main segments: the space segment (satellites), the control segment (ground stations), and the user segment (GPS receivers). GPS is used in a wide range of applications, including navigation, mapping, tracking, and timing.
Integrating GPS into PCB design involves using GPS modules, designing effective antennas, managing power efficiently, ensuring signal integrity, and thorough testing. Best practices include careful component placement, antenna clearance, shielding, ground plane implementation, stable power supply design, and following RF layout guidelines.
Categories: PCBA Manufacturing
Ground
Ground, also known as earth, is a reference point in an electrical circuit from which voltages are measured. It serves as a return path for electric current and is essential for the stable and safe operation of electronic devices. Proper grounding techniques, such as using ground planes, star grounding, separating analog and digital grounds, and employing shielding, are essential for maintaining signal integrity and reducing EMI.
Best practices for grounding in PCBA design include:
Continuous Ground Plane: Maintain a continuous ground plane on one of the PCB layers to provide a solid reference and reduce impedance. Avoid cutting or splitting the ground plane, as it can create ground loops and increase noise.
Minimize Ground Loops: Design the layout to minimize ground loops, which can introduce noise and interference. Use star grounding or single-point grounding to avoid loops.
Use Multiple Ground Vias: Use multiple vias to connect components to the ground plane, especially in high-frequency circuits, to reduce inductive effects and improve grounding.
Isolate Noisy Components: Isolate noisy components, such as switching regulators and oscillators, from sensitive analog circuits by placing them in separate areas of the PCB and using separate ground planes if necessary.
Categories: PCBA Manufacturing
Ground Plane
A ground plane is a large area of copper on a PCB that is connected to the ground pin of the power supply. It typically occupies an entire layer in a multilayer PCB or significant portions of the top and bottom layers in a two-layer board. The ground plane serves as a common return path for electrical current and helps stabilize the voltage levels across the PCB.
Categories: PCBA Manufacturing
GSM, Global System for Mobile Communication
The Global System for Mobile Communications (GSM) is a standard developed to describe protocols for second-generation (2G) digital cellular networks. Proper integration of GSM modules in PCB design involves considerations for antenna design, power management, and signal integrity to ensure reliable and efficient communication.
Categories: PCBA Manufacturing
HASL, Hot Air Solder Levelling
HASL (Hot Air Solder Leveling) is a surface finish process in which a thin layer of solder is applied to the exposed copper areas of a PCB. The board is then passed through hot air knives that remove excess solder and ensure a uniform coating. This process helps protect the copper from oxidation and provides a solderable surface for component assembly.
HASL offers advantages such as cost-effectiveness, excellent solderability, and reworkability, it also has some limitations, including uneven surfaces and potential thermal stress.
Categories: PCBA Manufacturing
Hatch Impedance
Hatch impedance refers to the impedance characteristics of a PCB trace that is designed with a hatch pattern. A hatch pattern, also known as cross-hatching, involves creating a series of parallel lines or a grid-like pattern on a copper plane, rather than using a solid fill. This technique is often used to control the impedance of the trace while reducing the amount of copper used, which can help with weight reduction and thermal management.
Categories: PCBA Manufacturing
HDL, Hardware Description Language
HDL is a specialized computer language used to describe the structure, behavior, and operation of electronic circuits, particularly digital logic circuits. The two most common HDLs are VHDL (VHSIC Hardware Description Language) and Verilog. HDLs allow designers to model and simulate electronic systems before physically building them, enabling efficient verification and debugging of complex designs. HDLs are used in the design and development of integrated circuits (ICs), field-programmable gate arrays (FPGAs), and application-specific integrated circuits (ASICs).
Categories: PCBA Manufacturing
Hertz
Hertz (Hz) is the unit of frequency in the International System of Units (SI), equivalent to one cycle per second.
Categories: PCBA Manufacturing
Hot Spot
Hot Spot refers to a localized area on the PCB that experiences a significant temperature rise during operation. This can lead to several potential problems:
Component Damage: Excessive heat can damage electronic components, reducing their lifespan or causing premature failure.
Solder Joint Degradation: High temperatures can weaken solder joints, potentially leading to electrical connection issues.
Warpage or Delamination: In extreme cases, heat can cause the PCB to warp or delaminate (layers separating).
Use thermal imaging cameras to find hot spots on the PCBA. Carefully placed components, proper power management, and heat sink design can prevent them. Thermal vias also help dissipate heat by transferring it to outer layers.
Categories: PCBA Manufacturing
Housing
Housing refers to the enclosure that protects the PCB and its components. The housing provides several functions:
Physical Protection: Shields the PCB from physical damage, dust, and moisture.
Electromagnetic Shielding: Certain housing materials can help shield the PCB and its components from electromagnetic interference (EMI) or radio frequency interference (RFI).
Heat Dissipation: The housing design can be optimized to facilitate heat dissipation from the PCB, aiding in thermal management.
Categories: PCBA Manufacturing
Hybrid Circuit
A Hybrid Circuit is a PCB that integrates components from different manufacturing technologies on a single board. This allows combining the advantages of various technologies to achieve desired functionalities in a compact package. However, hybrid circuits are harder and pricier to make than simple PCBs. They may have lower performance than advanced integrated circuits.
Categories: PCBA Manufacturing
ICT, In-Circuit Test
An In-Circuit Test (ICT) is an automated testing process performed after components are soldered onto the printed circuit board (PCB). It's a crucial step to ensure the electrical functionality and integrity of the assembled PCB before it moves on to further testing or mass production. ICTs catch manufacturing issues or component failures early in the manufacturing process and saves time and money by preventing defective PCBAs from moving forward in production.
Categories: PCBA Manufacturing
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is a professional association dedicated to development and standardization of technologies, including those related to electrical engineering, electronics, computer science, and telecommunications. It is one of the world's largest technical professional organizations, with members in over 160 countries.
IEEE standards ensure interoperability, safety, and quality, while its publications and conferences disseminate cutting-edge research and innovations. IEEE’s networking opportunities, professional development programs, and technical resources support engineers and designers in staying updated with the latest technologies and best practices, contributing to the advancement of the electronics industry.
Categories: PCBA Manufacturing
Imaging
Imaging is the process of creating a detailed pattern on a PCB, typically using a photoresist material that is sensitive to light. The pattern defines where the copper on the PCB will be etched away and where it will remain, forming the circuit pathways.
Categories: PCBA Manufacturing
Immersion Plating
Immersion plating is a surface finishing process in which a metal is deposited onto a substrate (such as copper) without the use of an external electric current. The deposition occurs through a displacement reaction, where metal ions in the solution are reduced and deposited onto the substrate, displacing some of the substrate material.
Immersion plating provides a uniform metal coating that improves solderability, protects against oxidation, and enhances durability. However, it also has limitations, including limited thickness, process sensitivity, potential whisker growth, and cost.
Categories: PCBA Manufacturing
Impedance
Impedance (Z) is the measure of opposition that a circuit presents to the passage of alternating current (AC) and is expressed in ohms (Ω). It is a complex quantity, comprising both real (resistance) and imaginary (reactance) components.
Z = R+j(XL−XC)
where:
- R is the resistance,
- XL is the inductive reactance,
- XC is the capacitive reactance,
- j is the imaginary unit.
Categories: PCBA Manufacturing
Impedance Control
Impedance control refers to the process of designing PCB traces with a consistent characteristic impedance to match the impedance of the connected components and devices. The characteristic impedance of a trace depends on its geometry, the dielectric material of the PCB, and the proximity to the reference plane (ground or power plane).
Proper impedance control is essential for maintaining signal integrity, minimizing reflections, reducing EMI, and ensuring power integrity.
Categories: PCBA Manufacturing
Incandescence
Incandescence is the emission of light from a hot object as a result of thermal radiation. As the temperature of an object increases, it emits light at different wavelengths. Initially, this light is in the infrared spectrum and is not visible to the human eye. As the temperature increases further, the object starts to emit visible light, progressing from red to white as the temperature rises. Applications of incandescence include lighting, heating elements, industrial processes, thermographic cameras, and pyrometers.
Categories: PCBA Manufacturing
Inductance
Inductance (L) is a measure of the amount of magnetic flux generated for a given current flowing through a conductor or coil. It is measured in henries (H). The inductance of a component depends on its physical characteristics, such as the number of turns in a coil, the area of the coil, and the permeability of the core material.
Managing inductance is essential for maintaining signal integrity, reducing EMI, and ensuring the proper functioning of high-speed and high-frequency circuits.
Categories: PCBA Manufacturing
Infrared
Infrared (IR) is a type of electromagnetic radiation with wavelengths longer than visible light but shorter than microwaves. It is commonly used in various applications including remote sensing, communication, and thermal imaging.
Categories: PCBA Manufacturing
Integrate
Integrate typically refers to the process of combining various components, subsystems, and functionalities into a cohesive and functional electronic system. It is crucial for enhancing functionality, miniaturization, cost efficiency, performance, and reliability. Methods of integration include component integration, System-on-Chip (SoC), Multi-Chip Modules (MCM), and High-Density Interconnect (HDI) technology.
Categories: PCBA Manufacturing
IoT
The Internet of Things (IoT) refers to a network of physical devices embedded with sensors, processors, and software that connect to the internet and exchange data. Applications span smart homes, industrial IoT, healthcare, agriculture, transportation, and smart cities.
Impact of IoT on PCBA Manufacturing:
Increased Demand for Smaller, Low-Power PCBs: IoT devices are often compact and battery-powered, requiring PCBs with miniaturized components and optimized designs for low-power consumption.
Focus on Wireless Connectivity: Many IoT devices rely on wireless technologies like Bluetooth, Wi-Fi, or cellular networks to communicate. This necessitates the integration of appropriate wireless modules onto PCBs.
Advanced Sensor Integration: Sensing capabilities are a core aspect of many IoT devices. Contract manufacturers need to be adept at handling various types of sensors and integrating them seamlessly into PCB designs.
Categories: PCBA Manufacturing
IPC
IPC - Association Connecting Electronics Industries® - is a trade organization that sets the standards for excellence in the design, manufacturing, and assembly of electronic products, including PCBs. IPC standards reduce manufacturing defects and improve product reliability by establishing best practices for manufacturing.
Categories: PCBA Manufacturing
ISO
ISO, the International Organization for Standardization, is an independent, non-governmental international organization that develops and publishes standards to ensure quality, safety, efficiency, and interoperability of products, services, and systems across various industries. ISO standards are widely recognized and adopted globally, providing a common framework that facilitates international trade and promotes best practices.
Key ISO standards relevant to PCB design and manufacturing include ISO 9001 (Quality Management Systems), ISO 14001 (Environmental Management Systems), ISO 13485 (Medical Devices Quality Management Systems), ISO/IEC 17025 (Testing and Calibration Laboratories), and ISO 26262 (Functional Safety for Automotive). Benefits of ISO certification include enhanced reputation, market access, customer satisfaction, operational efficiency, regulatory compliance, and continuous improvement.
Categories: PCBA Manufacturing
ISP, in-system programming
In-System Programming (ISP) refers to the capability of programming or reprogramming a microcontroller, FPGA, or other programmable device directly on the PCB (Printed Circuit Board) without needing to remove the device from its environment. ISP is particularly useful for updating firmware, testing, and debugging during development and after the product has been deployed.
Benefits of ISP include the following:
Convenience: ISP allows for easy updates and changes to firmware or configuration, simplifying the development and maintenance process.
Cost-Effective: Reduces the need for expensive socketing solutions and avoids the risk of damage associated with repeated physical handling.
Time-Efficient: Speeds up the development and production process by allowing on-board programming and testing.
Flexibility: Enables in-field updates and bug fixes, extending the product’s lifecycle and adaptability to new requirements or standards.
Production Testing: Facilitates testing and quality assurance processes during manufacturing by allowing programming and verification of the device on the PCB.
Categories: PCBA Manufacturing
ITU, International Telecommunication Union
The International Telecommunication Union (ITU) is a specialized agency of the United Nations responsible for issues related to information and communication technologies (ICT). ITU plays a crucial role in coordinating global telecom standards, managing the radio-frequency spectrum, and promoting international cooperation in the development and use of telecommunications.
Functions and Activities of ITU
Standardization: ITU develops and publishes international standards (ITU Recommendations) that ensure the interoperability, reliability, and efficiency of telecommunications networks and services. These standards cover a wide range of topics, including broadband access, cybersecurity, and digital broadcasting.
Spectrum Management: ITU allocates global radio-frequency spectrum and satellite orbits, ensuring they are used efficiently and equitably. It coordinates efforts to prevent harmful interference between radio services in different countries.
Policy and Regulation: ITU provides a platform for member states and industry stakeholders to develop policies and regulatory frameworks that promote sustainable and inclusive growth in the telecommunications sector.
Capacity Building: ITU offers training, workshops, and technical assistance to build the capacity of member states, particularly in developing countries, to harness the benefits of ICTs.
Research and Statistics: ITU conducts research and provides statistical data on global telecommunications trends, helping policymakers and industry leaders make informed decisions.
Conferences and Assemblies: ITU organizes global conferences and assemblies where member states and industry representatives discuss and adopt policies, standards, and strategic plans for the future of telecommunications.
Categories: PCBA Manufacturing
JEDEC, Joint Electronic Device Engineering Council
JEDEC is a global industry group responsible for developing open standards for microelectronics.
For PCB assemblers, JEDEC standards are essential for ensuring component compatibility, reliability, and performance. JEDEC specifications cover a wide range, including:
Package outlines and dimensions: This ensures proper placement and fitment of components on the PCB.
Material properties and tolerances: JEDEC defines material specifications for components like resistors, capacitors, and integrated circuits, guaranteeing their functionality within a PCB's operating environment.
Marking and labeling: JEDEC standards establish guidelines for component identification markings, simplifying assembly and inventory management.
Testing methodologies: JEDEC defines test methods for evaluating component performance and reliability, crucial for PCBA manufacturers to ensure product quality.
Categories: PCBA Manufacturing
JTAG, Joint Test Action Group
JTAG is a standardized interface used for testing and debugging integrated circuits and PCBs. It defines a serial communication protocol and a set of test access points (TAPs) that allow for direct access to the pins of an IC. This access enables various operations, including boundary-scan testing, in-system programming, and debugging.
Categories: PCBA Manufacturing
Jump-scoring
Jump scoring is a technique used during the V-scoring process of Printed Circuit Board (PCB) assembly. V-scoring involves creating a precise groove, typically in a V-shape, partially through the PCB material. This groove allows for clean and easy separation of individual PCBs from a larger panel after fabrication.
However, for some PCBs, it's crucial to maintain connections between the individual boards and a surrounding "waste rail" during early assembly stages. This waste rail provides additional rigidity and support, especially for PCBs with:
Thin laminates: Thinner materials may be more susceptible to warping or damage during handling if separated prematurely.
Heavy components: PCBs with bulky or heavy components might benefit from the extra stability offered by the waste rail until these components are soldered in place.
Jump scoring addresses this challenge by allowing the V-scoring blade to "jump" over designated sections of the waste rail.
Categories: PCBA Manufacturing
KCL, Kirchhoff’s Current Law
Kirchhoff’s Current Law (KCL) states that the total current entering a junction (or node) in an electrical circuit must equal the total current leaving the junction. This is based on the principle of conservation of electric charge.
Categories: PCBA Manufacturing
KVL, Kirchhoff’s Voltage Law
Kirchhoff’s Voltage Law (KVL) states that the sum of all electrical potential differences (voltages) around any closed loop or mesh in a circuit is zero. This is based on the principle of conservation of energy.
Categories: PCBA Manufacturing
LAN, Local Area Network
LAN refers to a closed network system connecting various machines and devices within the factory environment. This network enables communication and data sharing between different components of the manufacturing process, such as CNC machines, pick-and-place equipment, soldering machines, inspection machines, inventory systems, and centralized computers for production processes and data analysis.
Categories: PCBA Manufacturing
Land Pattern
A land pattern, also known as a footprint, is a graphical representation on the PCB that defines the physical locations where component leads will be soldered. It includes information about the size, shape, and spacing of pads, as well as the placement of holes for through-hole components and surface mount technology (SMT) components.
Categories: PCBA Manufacturing
Laser Ablation
Laser ablation involves using a focused laser beam to remove material from a substrate through vaporization, sublimation, or chemical decomposition. The process can be finely controlled, making it suitable for creating detailed patterns and structures with high precision.
Advantages of laser ablation include high precision, non-contact processing, flexibility, minimal thermal damage, and automation potential. Best practices for laser ablation include optimizing laser parameters, ensuring material compatibility, using fume extraction and cooling systems, maintaining precision alignment, performing regular maintenance, monitoring the process, and implementing safety measures.
Categories: PCBA Manufacturing
Laser Drilling
Laser drilling is a precise and versatile technique used in PCB manufacturing to create small, high-aspect-ratio holes, such as microvias, blind vias, and buried vias. The process involves generating a high-intensity laser beam, focusing it onto the PCB surface, and vaporizing the material to form holes.
Laser drilling offers high precision, flexibility, minimal mechanical stress, and the ability to achieve high aspect ratios, making it ideal for advanced PCBs, including HDI, flex, and rigid-flex boards.
Categories: PCBA Manufacturing
Leakage
Leakage refers to the undesired flow of electric current from a point of higher potential to a point of lower potential through an unintended path. Ideally, current should only flow along designated pathways (traces) to power electronic components. Leakage disrupts this intended flow, potentially leading to several issues:
Reduced performance: Leakage current can divert power away from intended circuits, affecting component functionality and overall system performance.
Component damage: Excessive leakage current can generate heat, potentially damaging sensitive components on the PCB.
Malfunctions: Leakage can lead to unexpected electrical behavior and malfunctions within the circuit.
Categories: PCBA Manufacturing
Legend
The silkscreen layer of a PCB that provides markings for component reference designators, polarity symbols, and other information to aid in assembly and identification.
Categories: PCBA Manufacturing
Life Cycle Assessment
Life Cycle Assessment (LCA) is a systematic method used to assess the environmental impact of a product throughout its entire lifespan. LCA helps evaluate the environmental footprint of a printed circuit board from raw material extraction to final disposal or recycling.
Benefits of LCA include:
- Environmental Impact Reduction: LCA helps identify the stages in the PCB life cycle that have the highest environmental impacts, enabling targeted improvements to reduce these impacts.
- Regulatory Compliance: Ensures compliance with environmental regulations and standards, such as RoHS (Restriction of Hazardous Substances) and WEEE (Waste Electrical and Electronic Equipment).
- Improved resource efficiency: By understanding the environmental impact of resource consumption, manufacturers can optimize material usage and waste reduction strategies.
- Enhanced product sustainability: LCA promotes the development of more environmentally friendly PCBs, contributing to a greener electronics industry.
Categories: PCBA Manufacturing
Load
Load in an electrical circuit refers to any component or group of components that consume power. This could be a resistor, an LED, a motor, a sensor, or any other device that uses electricity to perform its function.
Categories: PCBA Manufacturing
Load Current
Load Current is the amount of electrical current flowing through the load. It is determined by the load's impedance and the applied voltage according to Ohm’s Law.
Categories: PCBA Manufacturing
Load Impedance
is the total opposition that a load offers to the flow of AC current. It is a combination of resistance (R), inductive reactance, and capacitive reactance.
Categories: PCBA Manufacturing
Load Regulation
Load Regulation refers to the ability of a power supply to maintain a constant output voltage despite changes in the load current. It is an important parameter for power supplies, especially in applications where stable voltage is critical.
Categories: PCBA Manufacturing
Logic
This refers to the underlying principles governing the operation of digital circuits. Digital circuits utilize a binary system, where electrical signals represent two distinct states, 0s and 1s, to perform various computational tasks. The fundamental building blocks of logic circuits are logic gates, which implement basic logical functions such as AND, OR, NOT, NAND, NOR, XOR, and XNOR. There are two types of logic circuits. There are two kinds of logic circuits, combinational and sequential. Combinational circuits only care about current inputs. Sequential circuits consider both current inputs and past states.
Categories: PCBA Manufacturing
Low Insertion Force
Low Insertion Force (LIF) refers to a type of connector design that requires minimal force to insert or remove a component, such as an IC (Integrated Circuit) or a plug. LIF connectors are commonly used to reduce mechanical stress on the components and the PCB during assembly and maintenance.
Categories: PCBA Manufacturing
Low Pass Filter
Low Pass Filter (LPF) is an electronic circuit that allows signals with a frequency lower than a certain cutoff frequency to pass through while attenuating higher-frequency signals. LPFs are used in various applications, including audio processing, communication systems, and signal conditioning.
LPFs can be of two types. There are passive low pass filters, which are constructed using passive components such as resistors, and capacitors or inductors. There are also active filters, which are constructed using active components like operational amplifiers (op-amps) along with resistors and capacitors to provide gain and improved performance.
Categories: PCBA Manufacturing
Manufacturability
Manufacturability, specifically Design for Manufacturability (DFM), is the practice of designing PCBAs in such a way that they are easy to manufacture. This approach aims to minimize manufacturing costs, reduce production time, and ensure product quality and reliability. DFM involves taking into account the capabilities and limitations of manufacturing processes and equipment.
By following best practices for manufacturability, designers can reduce costs, improve efficiency, ensure quality, and accelerate time-to-market for their products. Incorporating manufacturability considerations early in the design process helps to avoid potential production issues and facilitates smooth scaling to mass production.
Categories: PCBA Manufacturing
Micro-Sectioning
Micro-sectioning, also known as cross-sectioning, is a precise technique used in the analysis and inspection of PCBAs and other electronic components. It involves cutting a small, well-defined sample from the PCB or component for detailed examination.
Benefits of micro-sectioning:
Defect identification: Micro-sectioning allows for visualization of internal defects such as voids, cracks, and delamination within the PCB structure, helping to identify and troubleshoot manufacturing issues.
Failure Analysis: When a PCB fails, micro-sectioning can be used to investigate the root cause by revealing issues such as voids, cracks, delamination, and improper soldering.
Process Validation: Manufacturers use micro-sectioning to validate their processes, ensuring that each step in the PCB fabrication and assembly produces the desired results.
Material analysis: Micro-sectioning enables the analysis of material properties within the PCB layers, ensuring they meet design specifications and contribute to optimal PCB performance.
Reverse engineering: Micro-sectioning can be used to analyze the construction of existing PCBs, aiding in the process of reverse engineering.
Categories: PCBA Manufacturing
Mil
In PCBA manufacturing, mil refers to a unit of length equal to one-thousandth (0.001) of an inch, which is also equivalent to 0.0254 millimeters. It's commonly used for measuring the diameter of wires used in PCB components and the thickness of coatings applied to PCBs, like solder mask or surface finishes.
Categories: PCBA Manufacturing
MO, Manufacturing Order
A Manufacturing Order (MO) is a formal document issued within a company to authorize the production of a specific quantity of PCBs. It serves as a green light for manufacturing and is typically associated with Gerber files and Bill of Materials (BOM) that provide the exact specifications for the PCB assembly.
Categories: PCBA Manufacturing
Modulation
Modulation is a technique used in communication systems to encode information onto a carrier signal. This process involves varying one or more properties of the carrier signal (such as amplitude, frequency, or phase) in accordance with the information signal.
Categories: PCBA Manufacturing
MOQ, Minimum Order Quantity
Minimum Order Quantity (MOQ) refers to the least number of PCB units a manufacturer is willing to produce in a single order. MOQs are set by the manufacturer and can vary widely from one to another depending on their capabilities.
Categories: PCBA Manufacturing
Motherboard
A motherboard refers to the main printed circuit board (PCB) within a computer system. It acts as the central hub, providing the electrical connections and communication pathways for all other components within the system.
Categories: PCBA Manufacturing
Mouse bites
Mouse bites refer to the small, perforated tabs used to connect PCBs in a panelized array. These tabs allow individual PCBs to be easily separated from the panel after the manufacturing process. Mouse bites create a weak point that can be broken manually or with minimal force, making the separation process convenient.
Categories: PCBA Manufacturing
MRP, Material Requirements Planning
In PCBA manufacturing, Material Requirements Planning (MRP) refers to a software system or a process that helps manufacturers plan and manage the materials needed for production. MRP ensures timely availability of materials, reduces inventory costs, and enhances purchasing efficiency and responsiveness. This can reduce product delays, minimize overstocking, optimize inventory levels, and allow production schedules to be adapted more quickly to demand fluctuations.
Categories: PCBA Manufacturing
Multimeter
A multimeter is a versatile electronic test instrument that typically combines the functionalities of a voltmeter (measures voltage), ammeter (measures current), and ohmmeter (measures resistance). Some advanced multimeters offer additional features like capacitance and inductance measurement. They are an essential tool for troubleshooting electrical faults and diagnosing component malfunctions.
Categories: PCBA Manufacturing
Mutual Inductance
Mutual inductance occurs when two inductors are placed close enough to each other that the magnetic field generated by one coil (the primary coil) links with the turns of the other coil (the secondary coil). When the current through the primary coil changes, it induces an electromotive force (EMF) in the secondary coil according to Faraday’s Law of Induction.
Categories: PCBA Manufacturing
NEMA
NEMA refers to the National Electrical Manufacturers Association. NEMA plays a crucial role in establishing electrical safety standards for electronic components and equipment by developing and publishing industry standards for products like electrical enclosures, industrial control equipment, wiring devices, and low-voltages circuit breakers.
Categories: PCBA Manufacturing
Netlist
A netlist represents a machine-readable representation of a circuit's electrical connectivity. It's a text file containing a structured list of nets, which are groupings of electrical nodes with identical voltage potential. Each net entry references the connected components and their specific pins. This data facilitates various downstream processes, including Design for Manufacturability (DFM) checks, Computer-Aided Manufacturing (CAM) tool generation, and electrical testing during PCB assembly.
Categories: PCBA Manufacturing
Noise
Noise refers to any unwanted electrical signal that disrupts the intended operation of a circuit. It can manifest as voltage spikes, ground loops, or crosstalk between traces. Excessive noise can lead to malfunctions, signal integrity issues, and even device failure. Mitigation techniques include shielding, filtering, proper grounding, and careful PCB design.
Categories: PCBA Manufacturing
Non-Volatile Memory
Non-volatile memory (NVM) is a type of memory that retains its data even after the power supply is turned off. This contrasts with volatile memory (RAM), which loses its data when power is lost. NVMs are essential components in PCBAs for storing critical information like configuration settings, program code, and user data.
Types of NVM commonly used:
Flash memory: Widely used for its versatility, affordability, and ease of programmability. Examples include SD cards, USB drives, and embedded flash chips.
EEPROM (Electrically Erasable Programmable Read-Only Memory): Offers reprogrammability while retaining non-volatile characteristics. Useful for storing configuration data that may need occasional updates.
PROM (Programmable Read-Only Memory): Permanently programmed during manufacturing, ideal for storing unchanging program code.
Categories: PCBA Manufacturing
Nonwetting
Nonwetting refers to the failure of solder to properly adhere to the surface of a component lead or PCB pad during the soldering process. This defect can lead to unreliable electrical connections and mechanical failures. Causes of nonwetting include:
Contaminated Surfaces: Oxides, oils, and other contaminants on the component leads or PCB pads can prevent proper wetting.
Insufficient Heat: Not applying enough heat to melt the solder completely and form a good bond.
Incompatible Materials: Using solder that is not compatible with the materials being soldered, such as certain lead-free solders with traditional tin-lead coatings.
Poor Solderability: Components or PCB pads that do not have a solderable finish.
Prevention involves cleaning surfaces, using appropriate solder and flux, ensuring sufficient heat, and proper storage.
Categories: PCBA Manufacturing
NPD, New Product Development
New product development (NPD) is the entire process of bringing a new electronic product from concept to production. It encompasses a series of stages, typically including:
Ideation and concept generation: Identifying a market need and brainstorming potential product solutions.
Design and development: Engineering the product, including schematics, PCB layout, component selection, and prototyping.
Testing and validation: Evaluating the functionality, performance, and reliability of the prototype.
Manufacturing process development: Establishing efficient and cost-effective production methods.
Launch and market introduction: Bringing the final product to market through marketing and sales channels.
Categories: PCBA Manufacturing
NPI, New Product Introduction
New product introduction (NPI) refers to the specific stage of transitioning a developed product from the design phase into full-scale manufacturing. It involves activities like:
Design for manufacturability (DFM) review: Ensuring the design is optimized for efficient and high-yield production.
Bill of materials (BOM) finalization: Specifying the exact components and materials needed for production.
Supplier sourcing and qualification: Selecting reliable suppliers for components and materials.
Pilot production and testing: Conducting small-scale production runs to identify and address any manufacturing issues before mass production.
Production ramp-up and volume manufacturing: Scaling up production to meet market demand.
Categories: PCBA Manufacturing
NRE, Non-Recurring Engineering
In PCBA manufacturing, Non-Recurring Engineering (NRE) costs represent the one-time expenses incurred during the development and initial setup of a new Printed Circuit Board Assembly (PCBA) design. These costs encompass all activities necessary to bring the design from concept to production readiness, excluding the ongoing per-unit costs of components and materials used in volume manufacturing. These one-time costs include things like design engineering fees, developing stencils and test fixtures, and functional and reliability testing.
Categories: PCBA Manufacturing
ODM, Original Design Manufacturer
An Original Design Manufacturer (ODM) is a company that designs and manufactures electronic products based on specifications provided by another company, often the brand owner. ODMs possess expertise in product development, engineering, and manufacturing, allowing them to offer a complete solution from concept to production.
Key characteristics of ODMs:
Design capabilities: ODMs can take client specifications and translate them into a functional product design, including schematics, PCB layout, and component selection.
Manufacturing expertise: ODMs have the infrastructure and capabilities for high-volume production of electronic products, ensuring quality and cost-effectiveness.
Private labeling: Products designed and manufactured by ODMs are typically private-labeled with the brand of the contracting company.
Using ODMs offers three main benefits. First, it reduces time-to-market. Second, it cuts development costs. Third, it enhances scalability.
Categories: PCBA Manufacturing
OEM, Original Equipment Manufacturer
An Original Equipment Manufacturer (OEM) is a company that designs and manufactures a product, but often sells it under another brand name. OEMs typically focus on core competencies like product design and marketing, and outsource the manufacturing process to contract manufacturers like MacroFab.
Benefits of using OEMs:
Focus on core competencies: Allows companies to concentrate on their strengths in design and marketing.
Reduced manufacturing risks: Outsourcing production minimizes investment in manufacturing infrastructure and personnel.
Flexibility: OEMs can partner with multiple contract manufacturers to source components and production capacity.
Categories: PCBA Manufacturing
Ohm
The ohm (Ω) is the unit of electrical resistance in the International System of Units (SI). It's named after German physicist Georg Ohm, who discovered the relationship between voltage, current, and resistance (Ohm's Law).
Categories: PCBA Manufacturing
Open
Open refers to a discontinuity in a circuit path. This can occur due to:
- Unpopulated footprints: Missing components on the PCB that should be populated according to the design.
- Solder defects: Incomplete or poorly formed solder joints that fail to create a proper electrical connection.
- Etching issues: Breaks or gaps in the conductive traces due to etching problems during PCB fabrication.
Opens can lead to circuit malfunctions and require troubleshooting to identify and fix the faulty connection.
Categories: PCBA Manufacturing
Open Loop Gain
Open loop gain is a term used in the context of operational amplifiers (op-amps) and other feedback systems. It refers to the gain of the amplifier when no feedback is applied to the circuit. Essentially, it is the ratio of the output signal to the input signal when the feedback loop is open. Open loop gain is typically very high in op-amps, often in the range of tens of thousands or more. However, because it is so high, the gain without feedback is impractical for most applications due to sensitivity to input signal changes and other factors. Therefore, feedback is usually applied to control and stabilize the gain.
Categories: PCBA Manufacturing
Outgassing
Outgassing refers to the release of gas that was trapped, dissolved, or absorbed in a material. In PCBA manufacturing, outgassing can occur from materials like solder masks, adhesives, and laminates, potentially causing problems in certain environments, such as vacuum or high-reliability applications. These gases can:
Corrode components: Outgassed chemicals can react with components and lead to premature failure.
Contaminate sensitive devices: Sensitive electronic components can be susceptible to damage from outgassed contaminants.
Reduce PCBA lifetime: Outgassing can affect the reliability and longevity of PCBs, especially in sealed or vacuum environments.
To control and reduce outgassing, use low-outgassing materials for components. Also, pre-baking certain components before assembly can remove trapped gasses.
Categories: PCBA Manufacturing
Output Impedance
Output Impedance refers to the opposition to current flow at the output terminal of a circuit. It affects how the output signal is delivered to the load and how the circuit interacts with connected devices. Matching the output impedance of a driver with the input impedance of a receiver is crucial for maintaining signal integrity and minimizing reflections.
Categories: PCBA Manufacturing
Panel
In PCBA manufacturing, a panel is a large sheet of material, typically rigid and flame-retardant, containing multiple copies of the same PCB design arranged in a precise grid pattern. These panels optimize the efficiency of fabrication and assembly processes. After assembly, the individual PCBs are separated from the panel using a depanelization process. Standard panel sizes include 18" x 24" but can vary depending on the manufacturer's capabilities and the specific PCB design requirements.
Categories: PCBA Manufacturing
Panelize
The process of arranging multiple copies of a PCB design onto a larger sheet (panel) for efficient fabrication and assembly.
Categories: PCBA Manufacturing
PCB Layout
PCB layout refers to the process of strategically placing electronic components and routing their electrical connections on a blank circuit board. This digital blueprint defines the physical design of the board, ensuring functionality, manufacturability, and performance. PCB layout includes
Component Placement: Strategic positioning of components for efficient routing, minimizing signal interference, and optimizing heat dissipation.
Signal Routing: Planning and creating electrical pathways (traces) that connect components while adhering to design rules for signal integrity and manufacturability.
Layer Stackup: Determining the number of conductive layers and their arrangement within the PCB to accommodate signal routing complexity and power requirements.
Design Rules: Following a set of electrical and physical guidelines to ensure the board functions correctly, can be manufactured reliably, and meets industry standards.
Categories: PCBA Manufacturing
Peel Strength
Peel Strength is the measure of adhesion between the layers of a PCBA, particularly the copper foil and the substrate. It is defined as the force required to peel a unit width of copper from the substrate under specified conditions. It's relevant for evaluating the adhesion between:
Solder joints and components: Strong peel strength ensures a reliable connection between components and the PCB. This connection withstands stress and vibration, preventing detachment.
Protective coatings and the PCB surface: Coatings like conformal coatings shield the board. Their peel strength shows how well they resist coming off or flaking off the board.
Categories: PCBA Manufacturing
Photoconductivity
Photoconductivity is the increase in electrical conductivity of a material when exposed to light. Photoconductive materials are used in processes like photolithography, where patterns are transferred onto the PCB using light. When exposed to light, these materials change their electrical properties, allowing specific areas of the PCB to be developed or etched to create the desired circuit patterns.
Photoconductive sensors can be used in automated optical inspection (AOI) systems to detect defects on PCBs based on their light-reflecting properties.
Categories: PCBA Manufacturing
Photoplotter
A photoplotter is a high-precision machine that generates a critical component called a phototool. This phototool, often a film sheet, acts as a master template used to transfer circuit patterns onto the copper layers of a PCB. A photoplotter receives a digital PCB design (which is typically in Gerber format) and creates a high-resolution image based on the design with the help of a computer-controlled laser beam.
Categories: PCBA Manufacturing
Photoresist
Photoresist is a light-sensitive material used in PCB fabrication to create the desired circuit pattern on the board. It consists of a light-sensitive polymer coated onto a substrate. When exposed to light through a photomask, the photoresist undergoes a chemical change, allowing selective removal of either the exposed or unexposed regions. This process creates the intricate patterns of the PCB's circuitry. There are two main types of photoresists: positive and negative. In positive photoresists, the exposed areas become soluble and are removed, whereas in negative photoresists, the exposed areas become insoluble and remain.
Categories: PCBA Manufacturing
Pick-And-Place
A pick-and-place (PnP) machine is a high-speed automated system that precisely places electronic components onto bare PCBs. These components, often surface-mount devices (SMDs), are tiny and require meticulous positioning for proper functionality and assembly. Pick-and-place machines are essential tools in modern PCBA manufacturing, enabling high-speed, precise, and cost-effective assembly of electronic devices.
Categories: PCBA Manufacturing
Pitch
Pitch refers to the center-to-center distance between adjacent features, such as pads or traces, on a PCBA. . Smaller pitch values indicate more closely spaced features, which is common in high-density interconnect (HDI) boards. Accurate control of pitch is essential to ensure that components fit correctly and that the board functions as intended without short circuits or signal integrity issues.
Categories: PCBA Manufacturing
PIV, Peak Inverse Voltage
Peak Inverse Voltage (PIV) is the maximum voltage a diode can withstand in the reverse-bias direction without breaking down. PIV is an important specification for diodes, especially in rectifiers used in power supplies. If the reverse voltage exceeds the PIV rating, the diode can break down and fail, potentially damaging the circuit. Therefore, selecting a diode with an appropriate PIV rating ensures reliable operation under expected voltage conditions.
Categories: PCBA Manufacturing
Plasma Etching
Plasma etching is a process used to remove material from the surface of a substrate using plasma, which is a highly reactive ionized gas. Plasma etching is utilized to precisely etch or clean surfaces, particularly when dealing with fine features and high-density interconnects. The plasma generates reactive species that chemically react with the material on the substrate, removing it layer by layer. This process allows for greater control over etching profiles and is especially useful for producing intricate patterns and small feature sizes in modern PCBAs.
Categories: PCBA Manufacturing
Plating
Plating is the process of depositing a layer of metal onto the surface of a PCB to improve conductivity, protect against corrosion, or enhance solderability. There are several types of plating processes, including:
Electroplating: Uses an electric current to deposit metal ions onto the PCB.
Electroless Plating: Uses a chemical reaction to deposit metal without the need for an electric current.
Hot Air Solder Leveling (HASL): Involves coating the PCB with molten solder and then removing excess solder with hot air to create a smooth, leveled surface.
Categories: PCBA Manufacturing
PN, Part Number
The PN (Part Number) is a unique identifier assigned to a specific component, PCB design, or assembled PCBA (Printed Circuit Board Assembly). It serves as a critical reference point throughout the entire manufacturing process, from ordering components to managing inventory and ensuring traceability. The part number is used for identification, procurement, inventory management, to track components and boards throughout production, and to ensure consistent documentation.
Categories: PCBA Manufacturing
PO, Purchase Order
A PO (Purchase Order) is a formal document issued by a company (the buyer) to a supplier (the seller). It serves as a legally binding agreement outlining the specific details of a PCB assembly purchase. Purchase orders typically include
Bill of Materials (BOM): A detailed list of all components required for the PCB assembly, including part numbers, quantities, and any relevant specifications.
- Quantity: The total number of PCB assemblies to be purchased.
- Delivery Schedule: The timeframe for delivery of the completed PCB assemblies.
- Pricing and Payment Terms: Clear definition of the agreed-upon price per PCB assembly and the payment terms (e.g., net 30 days).
- Quality Standards: Reference to the expected quality standards for the PCB assemblies, potentially including industry certifications or specific inspection criteria.
- Inspection and Testing: Outline of any required inspection and testing procedures to be performed on the PCB assemblies before acceptance.
- Warranty: Details of the warranty offered by the supplier on the PCB assemblies.
By issuing well-defined purchase orders, PCBA manufacturers can ensure a smooth and efficient procurement process, clear communication with suppliers, and well-documented agreements for their PCB assembly needs.
Categories: PCBA Manufacturing
Polarity
Polarity refers to the direction of electrical flow in a circuit, indicating the positive and negative sides. In direct current (DC) circuits, polarity is crucial because the current flows in one direction from the positive terminal to the negative terminal. Proper polarity ensures that components like diodes, electrolytic capacitors, and transistors function correctly. Incorrect polarity can damage these components or cause the circuit to malfunction.
Find out more about electrolytic capacitor polarity now.
Categories: PCBA Manufacturing
Polarized
A component is said to be polarized if it has a specific orientation for correct operation, meaning it must be connected in a certain way within the circuit. Common polarized components include electrolytic capacitors, diodes, and LEDs. These components have marked positive (anode) and negative (cathode) terminals. Ensuring correct orientation is essential for their proper functioning and to avoid damage.
Categories: PCBA Manufacturing
Populate
In PCBA (Printed Circuit Board Assembly) manufacturing, "populate" refers to the act of filling a bare PCB (printed circuit board) with its electronic components. This process typically involves using a Pick-and-Place machine (PnP) to precisely place each component onto the designated locations on the board.
Categories: PCBA Manufacturing
Power Dissipation
Power dissipation refers to the process by which an electronic component converts electrical energy into heat. It is a critical factor in circuit design, as excessive heat can damage components and affect performance. Managing power dissipation involves using heat sinks, fans, or thermal pads to dissipate heat and maintain safe operating temperatures.
Categories: PCBA Manufacturing
Prepreg
Prepreg is a critical material that acts as the insulating layer between different parts of a multilayer PCB. It's essentially a sheet of reinforcing fabric, typically fiberglass, pre-impregnated (pre-preg) with a partially cured resin.
Prepreg acts as both an insulator separating conductive layers to prevent shorts, and a binding agent that glues the board together during lamination, also enhancing its rigidity. Choosing the right prepreg requires considering resin type (for heat, electrical performance, etc.), weave style (affecting electrical properties and thickness), and overall thickness for consistent electrical behavior within the PCB. Prepreg offers several advantages in PCBs. It allows building complex boards with multiple layers, fitting more functionality into a smaller space. Additionally, the material's properties ensure clean signal transmission and a robust structure, making prepreg vital for high-performance PCBs.
Categories: PCBA Manufacturing
Press-Fit
Press-fit refers to a type of connection where a component is inserted into a hole on the PCB with enough force to create a reliable electrical and mechanical connection without the need for solder. The press-fit pins have a slightly larger diameter than the hole, causing them to deform slightly when inserted, which ensures a firm connection. This method offers several advantages, including ease of assembly, reworkability, and reliable connections without the thermal stress associated with soldering.
Categories: PCBA Manufacturing
Product Life Cycle
The product life cycle (PLC) is a model that describes the stages a product goes through from its introduction to its eventual decline and withdrawal from the market. The typical stages include:
- Development: Designing and creating prototypes.
- Introduction: Launching the product into the market.
- Growth: Increasing production and sales as the product gains acceptance.
- Maturity: Peak production and sales, with the market becoming saturated.
- Decline: Sales begin to fall due to competition, new technologies, or market saturation. Then, they eventually phase-out.
Understanding the product life cycle helps manufacturers plan production, manage resources, and make strategic decisions about product updates and new introductions.
Categories: PCBA Manufacturing
Prototype
A prototype is an early sample or model of a product used to test and validate its design, functionality, and performance before mass production. Prototypes allow designers to identify and fix issues, test different materials and processes, and refine the final product. This stage helps to minimize the risk of errors and defects in the final production run, saving time and costs.
Categories: PCBA Manufacturing
Prototyping
Prototyping is the process of creating a prototype. Depending on the complexity and intended use of the prototype, various techniques can be employed:
- Breadboarding: Using pre-fabricated components on a breadboard to quickly test basic circuit functionality.
- Functional prototyping: Creating a more advanced prototype that closely resembles the final product in terms of functionality.
- Rapid prototyping: Using techniques like 3D printing or CNC machining to create prototypes quickly for design iteration and testing.
Categories: PCBA Manufacturing
Rectification
Rectification is the process of converting alternating current (AC) to direct current (DC). Rectification is typically achieved using diodes, which allow current to flow in only one direction. This process is essential in power supplies, where AC from the mains is converted to the DC needed by electronic devices. There are different types of rectifiers, such as half-wave rectifiers, which use a single diode, and full-wave rectifiers, which use multiple diodes to convert both halves of the AC waveform to DC.
Categories: PCBA Manufacturing
Reflow Soldering
Reflow soldering is a widely used technique for attaching electronic components, especially surface-mount devices (SMDs), to printed circuit boards (PCBs) in PCBA manufacturing. Here's a concise explanation:
- Process: A solder paste containing tiny metal spheres and flux is applied to designated spots on the PCB. Components are placed on the paste. The entire assembly then travels through a controlled-heat reflow oven.
- Soldering Action: As the temperature rises within the oven, the solder paste melts, forming strong electrical and mechanical connections between the component leads and the PCB pads.
- Benefits: Reflow soldering enables:
- Mass Production: Efficiently soldering numerous components simultaneously.
- Precision: Precise temperature control ensures reliable solder joints.
- Small Component Assembly: Ideal for tiny SMDs unsuitable for hand soldering.
Categories: PCBA Manufacturing
Register/Registration
In the context of PCBA manufacturing, both "register" and "registration" are relevant, but they refer to slightly different concepts:
Register: This refers to the act of placing or positioning a component on a PCB during the design phase. Imagine strategically "registering" each component on the virtual PCB layout to ensure proper functionality and manufacturability.
Registration: This signifies the precise location or footprint where a component will be placed on the final PCB. The registration data is typically derived from the PCB design and used during the manufacturing processes, such as pick-and-place for component placement.
Categories: PCBA Manufacturing
Resistance
Resistance is the opposition to the flow of electric current in a material. It is measured in ohms (Ω). . The resistance of a material is determined by its composition, length, and cross-sectional area, following Ohm’s Law, which states that the voltage (V) across a resistor is equal to the current (I) flowing through it times its resistance (R), or V = IR.
Categories: PCBA Manufacturing
Reverse Bias
Reverse bias is the condition in which a diode or other semiconductor device is connected so that it prevents current flow. Reverse bias is used in applications such as voltage regulation, signal modulation, and protecting circuits from voltage spikes. Zener diodes, for example, are designed to conduct in reverse bias under certain conditions, allowing them to stabilize voltage levels.
Categories: PCBA Manufacturing
RF, Radio Frequency
RF( Radio Frequency)refers to electronic circuits and devices that operate at high frequencies, typically ranging from 300 kHz to 300 GHz. These circuits are used in various applications like wireless communications, radio and television broadcasting, radar systems, and microwave devices. RF PCBs are designed to optimize performance at high frequencies using specialized materials with low dielectric loss and controlled impedance, and using metal enclosures and strategic via placement to reduce electromagnetic interference (EMI).
Categories: PCBA Manufacturing
RFID, Radio-Frequency Identification
RFID is a technology that uses electromagnetic fields to automatically identify and track tags attached to objects. RFID systems consist of a tag (which includes an antenna and a microchip) and a reader. The reader emits a radio-frequency signal that powers the tag and enables it to transmit its stored data back to the reader.
RFID is widely used in various applications, including inventory management, access control, and contactless payments. Tags can be passive (requiring no internal power source and relying on the reader’s signal) or active (containing their own power source for a longer range and more complex functionality).
Categories: PCBA Manufacturing
RFQ, Request for Quotation
An RFQ (Request for Quotation) is a formal document a company seeking PCB assembly services (the buyer) sends to potential suppliers (contract manufacturers). It essentially initiates the bidding process for a specific PCB assembly project. A well-defined RFQ is a crucial tool in PCBA manufacturing. It facilitates efficient communication, enables price comparison, and empowers buyers to select the most suitable contract manufacturer for their project needs.
Categories: PCBA Manufacturing
Rise Time
Rise time refers to the time it takes for a signal to transition from 10% to 90% (or sometimes 20% to 80%) of its final voltage level. It's a critical parameter for ensuring signal integrity and proper circuit function in both digital and analog systems. Faster rise times can create stronger EMI within the PCB assembly, potentially causing crosstalk (unintended signal coupling) between components. Slower rise times can lead to signal distortion or timing issues. Rise time can be affected by things like the speed and capacitance of components, trace length and impedance, and driver characteristics.
Categories: PCBA Manufacturing
RMA, Return Merchandise Authorization
An RMA (Return Merchandise Authorization) is a formal process established by a manufacturer to handle situations where a customer needs to return PCB assemblies because they have encountered a malfunction or an issue with defective components. Through the RMA process, the manufacturer will inspect returned units to determine the root cause of the problem, and then identify next steps which may include repair or rework, replacement, or issuing a credit for the returned assemblies. An RMA functions as a critical communication and tracking tool throughout the return process. By implementing a well-defined RMA process, PCBA manufacturers can effectively manage customer returns, minimize disruptions, and build stronger customer relationships.
Categories: PCBA Manufacturing
ROI
ROI refers to the measure of profitability gained from an investment in a process, technology, or service related to PCB assembly. It's a key metric used to evaluate the financial efficiency and effectiveness of decisions made throughout the manufacturing lifecycle. It is calculated as the ratio of the net profit from the investment to the initial cost of the investment, usually expressed as a percentage.
Categories: PCBA Manufacturing
RoHS, Restriction of Hazardous Substances
RoHS stands for Restriction of Hazardous Substances. This is a European Union (EU) directive that restricts the use of certain hazardous materials in electronic equipment, including Lead, Mercury, Cadmium, Hexavalent Chromium, Polybrominated Biphenyls, and Polybrominated Diphenyl Ethers.
To be sold legally in the EU market, PCB assemblies must comply with the RoHS directive.
Categories: PCBA Manufacturing
Saturation
In electronics, saturation refers to the operating condition of a transistor where an increase in the base current no longer produces a proportional increase in the collector current. This occurs because the transistor is "turned on" as much as it can be, and further changes in base current have minimal impact.
In digital circuits, saturation can slow down the switching speed of transistors as they transition between on and off states.
Categories: PCBA Manufacturing
Schematic
A schematic diagram, also known as a circuit diagram, visually represents the electrical connections, components, and functionalities of an electronic circuit. It utilizes standardized symbols to depict various electronic components like resistors, capacitors, and transistors. Lines represent the electrical pathways connecting these components.
Categories: PCBA Manufacturing
Sequencing
Sequencing refers to the order in which operations or processes are executed. Proper sequencing is critical to ensure efficient workflow, prevent errors, and maintain quality control. For example, in testing and programming sequences, certain tests or programming steps must occur in a specific order to validate the functionality of a PCBA correctly.
Categories: PCBA Manufacturing
Series Circuit
A series circuit is a type of electrical circuit in which components are connected end-to-end so that there is only one path for current to flow. The current in a series circuit is the same through all components, but the voltage across each component can vary. The total resistance in a series circuit is the sum of the individual resistances, and the total voltage is the sum of the voltages across each component. Series circuits are used in applications where the same current must flow through multiple components, such as in string lights or certain sensor arrays.
If one component in a series circuit fails, the entire circuit is broken and current stops flowing. Series circuits are simple to design and analyze but are less robust than parallel circuits because the failure of a single component affects the whole circuit.
Categories: PCBA Manufacturing
Shielding
Shielding is a technique used to protect electronic circuits from unwanted electromagnetic interference (EMI). It involves enclosing components or traces with conductive materials that absorb or deflect EMI signals. Shielding can be applied in several ways, including:
- Shielded Cables: Cables with a conductive layer surrounding the inner conductors to block EMI/RFI.
- Shielding Enclosures: Metal cases or covers that encase entire circuits or devices.
- PCB Shielding: Using ground planes, shielding traces, or specialized materials within the PCB itself to protect sensitive signals.
Shielding helps maintain signal integrity, reduces noise, and ensures the reliable performance of the PCBA in various environments. It also helps PCBAs to achieve compliance of EMI emission and immunity standards.
Categories: PCBA Manufacturing
Short Circuit
A short circuit is an electrical fault that occurs when a low-resistance connection forms between two points in an electric circuit, allowing an excessive amount of current to flow. Short circuits can happen due to various reasons, such as damaged insulation, faulty components, or conductive objects bridging circuit points.
A short circuit can cause components to overheat, potentially leading to damage or fire. Preventing short circuits involves careful design practices, such as maintaining adequate spacing between conductive paths, using proper insulation, and incorporating protective devices like fuses or circuit breakers. When a short circuit occurs, it needs to be identified and repaired quickly to restore normal operation and prevent further damage.
Categories: PCBA Manufacturing
Skin Effect
Skin effect is the tendency of alternating current (AC) to distribute itself within a conductor such that the current density is highest near the surface of the conductor and decreases with greater depths into the conductor. As frequency increases, the effective resistance of the conductor increases due to the skin effect, because the current is confined to a thinner layer near the surface.
In high-frequency applications, like RF circuits and high-speed digital signals, the skin effect can cause significant losses and signal attenuation. Designing PCBAs for high-frequency applications often involves using materials and techniques to mitigate the skin effect, such as using plated-through vias or surface-mount components to minimize current path length.
Categories: PCBA Manufacturing
Signal
A signal refers to an electrical or electromagnetic current that carries data or information from one place to another. In a PCBA, signals are the electrical pulses or waves that travel through the traces and components to perform the desired operations. Signal integrity is crucial in PCB design, especially for high-speed circuits, to ensure that the signals are transmitted without distortion, noise, or loss of data. Signal quality can be affected by factors like impedance mismatches, crosstalk, and electromagnetic interference (EMI).
Categories: PCBA Manufacturing
Signal Layer
A signal layer in a PCB is dedicated to routing signal traces. In multi-layer PCBAs, these layers are specifically designated for this purpose, separate from power and ground planes. This separation reduces noise and crosstalk, improving signal integrity. Signal layers can be on the outer surfaces of the PCB or within the inner layers in a multi-layer stack-up. Proper organization and design of signal layers are essential for achieving optimal performance in complex circuits, ensuring efficient routing with minimal interference.
Categories: PCBA Manufacturing
Signal Loss
Signal loss refers to the reduction in power or amplitude of an electrical signal as it travels through a medium, such as a PCB trace or a cable. Signal loss can occur due to various factors, including resistance, impedance mismatches, dielectric losses, and radiation. Signal loss can degrade the performance of a circuit, leading to errors or reduced efficiency, so managing and mitigating it is an important aspect of PCB design.
Techniques to reduce signal loss include using low-loss materials, proper impedance matching, minimizing trace lengths, and optimizing trace widths.
Categories: PCBA Manufacturing
Silkscreen
A silkscreen, also known as a silkscreen legend, refers to a layer of markings applied to the top surface of a PCB (printed circuit board). The silkscreen provides vital information for assembly, identification, and maintenance purposes, and may include component designators, polarity markings, logos or branding, and instructions or warnings about the PCB assembly.
Categories: PCBA Manufacturing
SMD, Solder Mask Defined
SMD (Solder Mask Defined) refers to a technique in PCB (printed circuit board) design where the solder mask opening defines the solderable area for surface-mount devices (SMDs). In simpler terms, the solder mask, a protective layer on the PCB, is strategically opened only where SMDs will be soldered. This creates a defined pad size for precise solder application during assembly.
Categories: PCBA Manufacturing
SMD, Surface Mount Device
An SMD (Surface Mount Device) is a tiny electronic component designed to be soldered directly onto the surface of a printed circuit board (PCB). Unlike traditional components with leads that insert into holes, SMDs have flat metallic contacts for soldering. This allows for:
- Smaller size: Enables building more compact and high-density PCBs.
- Faster assembly: SMT (Surface Mount Technology) uses machines for efficient placement of SMDs.
- Greater functionality: Smaller size allows for packing more features into a smaller device.
Categories: PCBA Manufacturing
SMT, Surface Mount Technology
SMT (Surface Mount Technology) is a widely used method for assembling PCBs (printed circuit boards) with SMDs (Surface Mount Devices). SMT is the dominant assembly technology for a vast range of electronic devices, including smartphones and tablets, laptops, consumer electronics, wearable devices, and medical devices. SMT plays a critical role in modern electronics manufacturing, enabling the creation of compact, high-performance devices at an efficient cost.
Categories: PCBA Manufacturing
Solder Bridging
Solder bridging is an unwanted connection between two or more adjacent solder pads or traces on a PCB, caused by excess solder. This can lead to short circuits, malfunctioning of the PCB, or even damage to the components. Solder bridging can happen during the soldering process due to incorrect solder paste application, improper component placement, or excessive solder. To prevent solder bridging, careful control of the soldering process, appropriate stencil design, and accurate placement of components are essential. Automated optical inspection (AOI) and manual inspection are also used to detect and correct solder bridges.
Categories: PCBA Manufacturing
Solder Leveling
Solder leveling, also known as Hot Air Solder Leveling (HASL), is a process used to apply and flatten solder on the surface of a PCB to create a smooth, even coating. In HASL, the PCB is dipped into molten solder. Then, it's exposed to hot air jets that blow off extra solder. This leaves a uniform coating of solder on the copper pads. This process ensures good solderability and protects the copper from oxidation. HASL can create an uneven surface, making it unsuitable for fine-pitch components. ENIG (Electroless Nickel Immersion Gold) or OSP (Organic Solderability Preservative), are better options for high-density boards requiring a flatter surface.
Categories: PCBA Manufacturing
Solder Mask Dam
The solder mask dam, also known as a solder resist dam, is a layer of photoresist applied to specific areas of the PCB during the manufacturing process. It acts as a barrier that prevents solder from adhering to those areas during the soldering process.
Solder mask dams are essential in fine-pitch components, such as BGAs (Ball Grid Arrays) or high-density connectors, where the risk of solder bridging is high. The solder mask material creates a physical barrier that helps contain the solder on each pad, preventing it from flowing and forming unintended connections.
Categories: PCBA Manufacturing
SOP, Start of Production
SOP, or Start of Production, is a key milestone in PCBA (Printed Circuit Board Assembly) manufacturing. It signifies the transition from the planning and preparation phase to the actual production of the PCB assemblies. By SOP, the PCB design has been reviewed, approved and finalized, the BoM(bill of materials) is finalized, and materials have been procured. Additionally, production equipment is set up and assembly processes are defined.
Categories: PCBA Manufacturing
SPI, Solder Paste Inspection
SPI, or Solder Paste Inspection, is a vital quality control step in the Surface Mount Technology (SMT) assembly process for PCBs (Printed Circuit Board Assemblies). SPI utilizes an automated optical inspection (AOI) system to meticulously examine the solder paste applied to the PCB surface before placing any components for missing solder paste, insufficient volume, bridging, or other defects. SPI catches solder paste defects early, improves yield, and prevents assembly defects that could lead to future device failures.
Categories: PCBA Manufacturing
Stackup
A stackup in PCB design refers to the arrangement and sequence of layers in a multilayer PCBA. It determines the number of layers, their thickness, and the materials used, affecting impedance, crosstalk, and electromagnetic interference (EMI) properties of the PCBA. A typical stackup may include:
- Signal Layers: Layers carrying electrical signals between components.
- Power Planes: Layers dedicated to distributing power across the PCB.
- Ground Planes: Layers providing a common return path for electrical currents.
Categories: PCBA Manufacturing
Stencil
A stencil is a thin metal or polymer sheet with openings that correspond to the pads on the PCB, used to apply solder paste to the PCB during the surface mount technology (SMT) assembly process. The stencil is placed over the PCB, and solder paste is spread across the stencil with a squeegee, filling the openings. When the stencil is removed, solder paste remains on the PCB pads, ready for component placement. Stencils are typically made from stainless steel or other durable materials to ensure precise and consistent application of solder paste.
Key characteristics of stencils:
- Aperture design: The stencil features precisely designed openings (apertures) corresponding to the footprints of surface mount components on the PCB.
- Material selection: Stencils are typically made from stainless steel due to its durability, heat resistance, and ability to maintain precise aperture shapes.
- Stencil thickness: The thickness of the stencil influences the amount of solder paste deposited onto the PCB pads.
Categories: PCBA Manufacturing
Subcontractor
A subcontractor, also known as a second-tier supplier, is a company that specializes in a specific aspect of PCBA manufacturing and provides its services to a contract manufacturer (CM) or original equipment manufacturer (OEM). Typical services offered by subcontractors:
- PCB fabrication: Manufacturing bare PCBs according to the design specifications provided by the CM or OEM.
- Component procurement: Sourcing electronic components based on the Bill of Materials (BOM) for the PCB assembly.
- Component testing: Performing pre-assembly testing of electronic components to ensure their functionality.
- Partial assembly: Completing specific stages of the PCB assembly process, such as soldering through-hole components.
Subcontractors bring expertise and specialization. They have knowledge and equipment for specific tasks, boosting quality. Subcontractors also help with cost and capacity. They're cost-effective and can handle production surges or complex projects.
Categories: PCBA Manufacturing
Surface Finish
Surface finish refers to the coating applied to the exposed copper surfaces of a PCB to protect them from oxidation and ensure good solderability. Common types of surface finishes in PCB manufacturing:
- HASL (Hot Air Solder Leveling): The PCB is dipped in molten solder and then leveled with hot air to create a uniform coating. It is cost-effective but may create an uneven surface.
- ENIG (Electroless Nickel Immersion Gold): A layer of nickel is plated onto the copper, followed by a thin layer of gold. ENIG provides a flat surface, excellent solderability, and good corrosion resistance.
- OSP (Organic Solderability Preservative): A thin organic layer is applied to protect the copper until soldering. OSP is environmentally friendly and provides a flat surface but may not be suitable for multiple reflows.
- Immersion Silver: A thin layer of silver is deposited on the copper. It offers good solderability and a flat surface but may tarnish over time.
- Immersion Tin: A layer of tin is deposited on the copper. It provides a flat surface and good solderability but can have shelf-life issues.
Choosing the right surface finish depends on the specific requirements of the PCBA application, such as assembly process, environmental conditions, and cost considerations.
Categories: PCBA Manufacturing
Surface Mount
Surface mount refers to a method for constructing electronic circuits in which the components are mounted directly onto the surface of a PCB. The surface mount components are also called Surface Mount Devices (SMDs). Surface Mount Technology (SMT) contrasts with through-hole technology, where component leads are inserted into holes drilled in the PCB. SMT offers several advantages:
- Higher Component Density: Components can be placed on both sides of the PCB, allowing for more compact and complex designs.
- Improved Performance: Shorter lead lengths and reduced parasitic elements improve high-frequency performance and signal integrity.
- Automation: SMT components are suitable for automated assembly processes, leading to faster production times and lower labor costs.
SMT has become the standard in modern electronics manufacturing due to its efficiency, reliability, and ability to support miniaturization of electronic devices. However, SMT has drawbacks. First, it requires high upfront costs for equipment and stencils. Second, inspecting and troubleshooting is harder due to small component size. Finally, not all components are available in surface mount packages.
Categories: PCBA Manufacturing
TAB-Tape Automated Bonding
TAB (Tape Automated Bonding) is a technique used to attach integrated circuits (ICs) or other electronic components to flexible circuit boards (FPCs). During Tape Automated Bonding, : ICs are mounted on a conductive tape carrier, then bonded to a flexible circuit board using thermocompression or ultrasonic techniques.
TAB enables building compact and flexible devices due to thin FPCs and tape carriers. It also allows for high-density connections, faster assembly, and potentially lower cost for high-volume production. TAB is commonly used in LCD displays, portable electronics, medical devices, and automotive electronics. While TAB offers advantages for miniaturization and high-density applications, wire bonding might be preferred for high-power connections or easier repairability.
Categories: PCBA Manufacturing
Tape and Reel
Tape and reel (T&R) is a standardized method for packaging and supplying surface mount components (SMCs) for automated assembly in PCBA manufacturing. The process involves feeding the tape through a pick-and-place machine, which picks the components from the tape and places them onto the PCB.
Tape and reel packaging offers many benefits. First, it boosts efficiency in high-speed assembly. Second, it shields components from damage and contamination. Third, it simplifies handling and inventory management.
Categories: PCBA Manufacturing
Temperature Coefficient
The temperature coefficient is a measure of how a component's electrical properties change with temperature. It is usually expressed in parts per million per degree Celsius (ppm/°C) or as a percentage per degree Celsius (%/°C). The temperature coefficient is critical for components like resistors, capacitors, and semiconductors, as it indicates how stable their performance is across different temperatures. For example:
- Positive Temperature Coefficient (PTC): The component's value increases with temperature.
- Negative Temperature Coefficient (NTC): The component's value decreases with temperature.
In PCBA design, understanding the temperature coefficient helps ensure that the circuit operates reliably under varying thermal conditions. Components with low temperature coefficients are preferred for applications requiring high precision and stability.
Categories: PCBA Manufacturing
Test Coupon
A test coupon is a small section of material included on the same panel as the final PCBs (printed circuit boards) during fabrication. It serves as a quality control tool to assess various aspects of the manufacturing process. If you wish to conduct destructive testing on this coupon, it can be embedded in clear plastic.
Categories: PCBA Manufacturing
Testing
Testing refers to the processes and techniques used to verify that a PCB and its assembled components function correctly and meet specified performance criteria. Various types of testing are performed at different stages of the manufacturing process:
Bare Board Testing:
- Electrical Test (ET): Checks for continuity (open circuits) and shorts in the bare PCB before components are assembled.
- Automated Optical Inspection (AOI): Uses cameras to inspect the PCB for defects, such as missing or misaligned features.
Assembly Testing:
- In-Circuit Testing (ICT): Tests individual components on the PCBA for correct placement and function. ICT can measure resistance, capacitance, and the operation of active devices.
- Functional Testing (FCT): Verifies that the assembled PCBA performs its intended function. This involves applying power and signals to the board and measuring the output.
- Boundary Scan: A technique used for testing digital circuits, especially those with complex interconnections, using a standardized interface (JTAG).
Environmental Testing:
- Thermal Cycling: Exposes the PCBA to extreme temperature variations to test its thermal reliability.
- Vibration Testing: Simulates the mechanical stresses that the PCBA might encounter during use.
- Humidity Testing: Assesses the PCBA's performance in high-humidity environments.
Testing helps identify and correct defects early in the manufacturing process, ensuring that only high-quality, reliable products reach the end-users.
Categories: PCBA Manufacturing
Thermal Conductivity
Thermal conductivity is a measure of a material's ability to conduct heat. In PCBA design, materials with high thermal conductivity are used to effectively transfer heat away from heat-generating components. Common materials with high thermal conductivity used in PCBs include copper, aluminum, and certain thermally conductive insulators. Good thermal conductivity helps prevent overheating, which can lead to component failure or reduced lifespan.
Categories: PCBA Manufacturing
Thermal Management
Thermal management refers to the techniques and materials used to control the temperature of electronic components and systems to ensure optimal performance and reliability. Various methods and materials are used for thermal management, including:
- Heat Sinks: Metal objects attached to heat-generating components to increase the surface area for heat dissipation.
- Thermal Interface Materials (TIMs): Materials placed between components and heat sinks to improve thermal transfer, such as thermal grease, pads, or tapes.
- Cooling Fans: Fans that force air over components to increase heat dissipation.
- Heat Pipes: Devices that transfer heat through phase change and capillary action.
- Thermal Vias: Copper-plated holes in PCBs that conduct heat from the top layer to the bottom layer or inner layers.
Effective thermal management ensures that electronic devices operate within safe temperature ranges, preventing overheating and enhancing their reliability and longevity.
Categories: PCBA Manufacturing
Thermal Resistance
Thermal resistance (θ, pronounced "theta") is a measure of a material's or component's ability to resist the flow of heat. Thermal resistance measures how well electronic components and systems handle heat. Lower thermal resistance indicates better heat dissipation.
Thermal resistance can be calculated for different parts of the thermal path, such as from the junction of a semiconductor device to the case (junction-to-case thermal resistance) or from the case to the ambient environment (case-to-ambient thermal resistance). The total thermal resistance is the sum of these individual resistances and determines the overall ability of a system to manage heat.
Categories: PCBA Manufacturing
Thermal Stability
Thermal stability refers to the ability of a material or a component to maintain its properties and performance under varying temperature conditions without undergoing significant degradation or change.
In PCBA design, thermal stability is vital. Components face various temperatures and cycles. High thermal stability protects against deformation, degradation, and electrical property loss from heat. For example, a stable PCB substrate ensures reliability, even when it heats up. The same goes for components like capacitors and resistors. They must be stable to work well in a wide temperature range.
Categories: PCBA Manufacturing
Thermal Stress
Thermal stress refers to the stress induced in a material or component due to changes in temperature, which cause expansion or contraction. In PCBA design, thermal stress can lead to issues like warping, delamination, and cracking of the board or components. Managing thermal stress is essential to ensure the longevity and reliability of the PCB. Techniques to mitigate thermal stress include:
- Using materials with similar coefficients of thermal expansion (CTE)
- Designing for thermal relief in high-stress areas
- Implementing controlled cooling and heating rates during manufacturing processes
Categories: PCBA Manufacturing
Time Constant
The time constant (τ, pronounced "tau") is a characteristic property of a system to respond to a change in input, typically to reach approximately 63.2% of its final value. In electronics, the time constant is particularly important in capacitive and inductive circuits. In capacitive circuits, the time constant indicates how quickly a capacitor charges or discharges through a resistor. In an inductive circuit, the time constant indicates how quickly the current through an inductor builds up or decays.
In thermal systems, the time constant can describe how quickly a component or material reaches thermal equilibrium after a change in temperature. For instance, a heat sink with a short thermal time constant will quickly adjust to changes in heat load, effectively maintaining the temperature of the component it cools.
Categories: PCBA Manufacturing
Tombstoning
Tombstoning is a soldering defect in surface mount technology (SMT) where one end of a component, typically a chip resistor or capacitor, lifts off the PCB, resembling a tombstone. Tombstoning occurs due to uneven wetting forces during the reflow soldering process. If one end of the component is heated and wetted with solder before the other, the surface tension can pull the component upright.
This defect leads to poor electrical connections and can render the PCB non-functional. Several factors contribute to tombstoning, including:
- Uneven heating: Variations in temperature across the PCB.
- Component placement: Misalignment or improper orientation.
- Solder paste application: Inconsistent or insufficient solder paste deposition.
To prevent tombstoning, manufacturers ensure even heating in the reflow oven, accurate component placement, and consistent solder paste application.
Categories: PCBA Manufacturing
Transmission
Transmission is a fundamental concept in PCB design, as it involves the transfer of signals across the board's traces and interconnects. Effective signal transmission hinges on several factors. Signal integrity ensures that signals maintain their quality and integrity without distortion or loss. Impedance matching prevents reflections. Reducing crosstalk minimizes interference.
Categories: PCBA Manufacturing
Turnkey
Turnkey means that the provider manages the entire production process, including design, fabrication, assembly, testing, and even procurement of components. Customers receive a complete, ready-to-use product without needing to manage individual steps.
Benefits of turnkey services include:
- Convenience: Customers deal with a single provider, simplifying project management.
- Efficiency: Streamlined processes reduce production time and costs.
- Quality Control: Consistent quality is maintained across all stages of production.
Turnkey solutions are particularly beneficial for companies without in-house manufacturing capabilities or those looking to expedite product development cycles. They allow companies to focus on design and innovation while leaving the manufacturing complexities to the experts.
Categories: PCBA Manufacturing
UL, Underwriter’s Laboratories
UL is a global independent safety certification company. They test and certify products for safety against potential hazards like fire, electrical shock, and other risks. Many countries and regions require UL certification for electronic devices to be legally sold in their markets.
Categories: PCBA Manufacturing
Unsaturated Logic
Unsaturated logic refers to a type of digital logic circuit where the transistors are operated in the active region (linear region) rather than the saturation region. In unsaturated logic circuits, transistors switch between different operating points within the active region, allowing for faster switching times compared to saturated logic circuits, where transistors fully turn on and off.
Examples of unsaturated logic families include:
- ECL (Emitter-Coupled Logic): Known for its high speed because transistors do not fully saturate, minimizing switching delay.
- TTL (Transistor-Transistor Logic): Can operate in both saturated and unsaturated modes, but higher-speed variants often operate in unsaturated mode to improve performance.
Unsaturated logic is used in applications requiring high-speed operation and low propagation delay, though it typically consumes more power than saturated logic.
Categories: PCBA Manufacturing
US-ASCII
US-ASCII (United States American Standard Code for Information Interchange) is a 7-bit encoding character set containing 128 characters, including:
- Control Characters: Non-printing characters used for text control (e.g., carriage return, line feed).
- Printable Characters: Includes letters (A-Z, a-z), digits (0-9), punctuation marks, and special symbols.
ASCII was developed in the 1960s and became the basis for many later encoding schemes, including ISO-8859-1 and UTF-8. It remains widely used for basic text representation, particularly in programming and data transmission.
Categories: PCBA Manufacturing
VA, Volt-Ampere
Volt-ampere (VA) is a unit of measurement for apparent power in an electrical circuit, equal to the product of the root mean square (RMS) voltage and RMS current. Apparent power is the combination of real power (measured in watts) and reactive power (measured in VARs, volt-ampere reactive).
In AC circuits, VA represents the total power supplied to the circuit, including both useful power and power lost due to reactive components. It is especially relevant in the context of power supplies and transformers, where it indicates the capacity to deliver power regardless of phase differences between voltage and current.
Categories: PCBA Manufacturing
Visual Inspection
Visual inspection is a process in quality control and assurance in PCBA manufacturing to identify defects, misalignments, or other issues using visual methods. There are two main types of visual inspection:
- Manual Visual Inspection: Performed by trained technicians using magnifying tools to examine the PCB for defects.
- Automated Optical Inspection (AOI): Uses cameras and image processing software to automatically scan the PCB and detect defects based on pre-programmed criteria.
Visual inspection ensures that any issues are identified and corrected before the PCBs are assembled into final products, improving reliability and reducing the risk of failures.
Categories: PCBA Manufacturing
Volt
The volt (V) is the derived unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). One volt is defined as the difference in electric potential between two points in a conductor when a current of one ampere dissipates one watt of power between those points. It measures the potential energy per unit charge.
Categories: PCBA Manufacturing
Voltage
Voltage, also known as electric potential difference, is the measure of the electric potential energy per unit charge between two points in an electrical field. It is measured in volts (V). Voltage is the driving force that pushes electric current through a circuit. It can be thought of as the electrical pressure that causes electrons to move.
Categories: PCBA Manufacturing
Voltage Breakdown
Voltage breakdown is the condition where an insulating material becomes conductive due to the application of a voltage higher than its breakdown voltage, causing a sudden increase in current. This can result in permanent damage to the material and surrounding components. In semiconductors, breakdown can occur in diodes, transistors, and other devices, often designed to handle such events under controlled conditions (e.g., Zener diodes). Engineers must ensure that components and materials are rated for voltages higher than the maximum expected in the application to avoid breakdown.
Categories: PCBA Manufacturing
Voltmeter
A voltmeter is an instrument used to measure the electrical potential difference (voltage) between two points in an electrical circuit. They can be analog or digital. Analog Voltmeters use a moving pointer to display voltage readings on a scale. Digital Voltmeters (DVM) display readings numerically, offering higher precision and easier readability. Modern digital multimeters (DMMs) can function as voltmeters, ammeters, and ohmmeters, providing versatile measurement capabilities in one device.
Categories: PCBA Manufacturing
Watt
Watt (W) is the SI unit of power. It measures the rate at which energy is transferred or converted. One watt is defined as one joule per second. In electrical terms, power (in watts) is the product of voltage (in volts) and current (in amperes).
which measures the rate at which energy is transferred or converted. One watt is defined as one joule per second.
Categories: PCBA Manufacturing
Wave
A wave is a disturbance or oscillation that travels through space and matter, transferring energy from one point to another without the permanent displacement of the medium. Understanding wave behavior is crucial for designing and analyzing circuits involving signal transmission, such as in RF (radio frequency) communication.
Categories: PCBA Manufacturing
Wave Soldering
Wave soldering is a high-volume soldering technique used in PCBA manufacturing to solder through-hole components (THT) onto a PCB. It involves passing the PCB over a wave of molten solder. The process involves several steps:
- Fluxing: Applying flux to the PCB to clean and prepare the surfaces for soldering.
- Preheating: Gradually heating the PCB to prevent thermal shock and ensure proper solder flow.
- Soldering: Passing the PCB over a wave of molten solder created by pumping solder through a nozzle. The wave coats the exposed metal surfaces, forming solder joints.
- Cooling: Allowing the solder to solidify, forming strong electrical and mechanical connections.
Categories: PCBA Manufacturing
Wavelength
Wavelength is the distance between successive crests, troughs, or identical points in a wave, typically measured in meters. It is a fundamental property of waves and is inversely related to frequency.
Categories: PCBA Manufacturing
Wet Mask
Wet mask refers to a type of solder mask applied to a PCB in liquid form before being cured to protect the board and define areas for soldering. The liquid is typically a liquid photoimageable (LPI) material. It is applied to the PCB through various methods, such as screen printing, curtain coating, or spraying.
Once applied, it is exposed to UV light through a photomask, which defines the areas where the solder mask will be removed. After exposure, the PCB is developed, washed, and cured, leaving a hardened protective layer. The solder mask prevents solder bridges,protects against environmental damage and enhances the PCBA's electrical performance.
Categories: PCBA Manufacturing
Whisker
A whisker is a thin, hair-like metallic filament that can grow spontaneously from the surface of metals, such as tin, zinc, or cadmium, often used in electronic components. Whiskers pose a significant reliability risk. They can cause short circuits, leading to device failure.
They can grow due to various factors, including mechanical stress, thermal cycling, and the presence of certain surface finishes. Strategies to mitigate whisker growth include,using alloyed finishes (e.g., tin-lead)
applying conformal coatings and implementing specific manufacturing processes and controls.
Categories: PCBA Manufacturing
WIP, Work in Progress
WIP refers to the partially finished PCB assemblies currently undergoing various stages of the assembly process. This includes components placed on the boards but not yet soldered, boards that have gone through soldering but not yet inspected, and so on. WIP represents the value of all these partially completed assemblies. Minimizing WIP is often desirable for manufacturers as it reduces the amount of tied-up capital in partially finished goods.
Categories: PCBA Manufacturing
Wire Bonding
Wire bonding is a well-established technique used to create electrical interconnections between integrated circuits (ICs) or other semiconductor devices and their packaging during PCB (printed circuit board) fabrication. It can also be used to connect ICs to other electronic components or even directly to a PCB. This is a well-established and reliable process with a long history of successful use. However, compared to newer technologies like TAB, wire bonding can result in a larger footprint for the interconnected components.
Categories: PCBA Manufacturing
Wire Wrap Area
A wire wrap area is a designated section on a PCB or prototype board where components are connected using wire wrap technology, instead of traditional soldering. Wire wrap is a method of making electrical connections by wrapping a wire around a terminal post at high tension. This method was widely used for prototyping and small-scale production before the advent of modern PCB manufacturing techniques. The wire wrap area typically includes a grid of pins or posts where wires can be wrapped to create connections.
Key features and benefits include:
- Reworkability: Easy to modify and troubleshoot connections without soldering.
- Reliability: Wire wrap connections are known for their strong mechanical and electrical integrity.
- Flexibility: Suitable for prototyping and experimental setups where circuit changes are frequent.
While less common today, wire wrap areas can still be found in some educational kits and certain legacy systems.
Categories: PCBA Manufacturing
Yield
Yield refers to the proportion of functional, defect-free units produced in a manufacturing process, typically expressed as a percentage of the total units produced. A high yield indicates a well-optimized process with minimal defects, while a low yield suggests issues that need to be addressed.
Yield can be categorized into:
- First Pass Yield (FPY): The percentage of units that pass all tests and inspections without requiring rework.
- Final Yield: The percentage of units that are functional after any necessary rework or repairs.
Categories: PCBA Manufacturing
Active Components
In Printed Circuit Board Assembly (PCBA), active components are electronic devices that can amplify, switch, or generate electrical signals. Active components form the heart of a circuit's functionality, performing tasks like processing information, controlling power flow, and generating outputs. Active components require an external power supply–typically DC voltage–to operate. Examples of active components include integrated circuits (ICs), transistors, diodes, and optoelectronic devices like LEDs, photodiodes, and optocouplers.
Categories: Board Parts / Components
Amplifier
Amplifiers are crucial electronic circuits that play a vital role in manipulating electrical signals. Their primary function is to take a weak input signal and produce a stronger output signal with the same characteristics. Amplifiers find a use in a wide range of PCBA applications including signal boosting, driving loads, and signal conditioning.
Categories: Board Parts / Components
Analog Circuit
An analog circuit is an electronic pathway designed to handle continuously variable electrical signals. These signals fluctuate smoothly, mimicking the real-world phenomena they represent, such as temperature, sound, or light. Unlike digital circuits that operate with discrete voltage levels (0 or 1), analog circuits work across a spectrum of voltages or currents. Analog circuits are often used for preparing sensor signals for further processing by amplifying weak signals or filtering out noise, for power management, and for amplification, mixing, and modulation.
Categories: Board Parts / Components
Annular Ring
An annular ring refers to the ring-shaped area of copper surrounding a plated through-hole or via. It essentially forms the landing zone for components on the PCB. The annular ring provides sufficient surface area for solder to adhere during the assembly process and offers mechanical support for the component lead.
Categories: Board Parts / Components
Anode
An anode refers to the electrode within a polarized electrical component through which current flows in from an outside circuit. During operation, electrons typically flow out of the anode and into the external circuit. This contrasts with the cathode, where electrons enter.
Categories: Board Parts / Components
ANSI
ANSI stands for the American National Standards Institute. While ANSI itself doesn't directly create standards for PCB manufacturing, it plays a crucial role in overseeing the development and publication of industry standards through collaborations with other organizations, specifically the IPC - Association Connecting Electronics Industries.
Categories: Board Parts / Components
AQL, Acceptable Quality Level
AQL stands for Acceptable Quality Level. It's a statistical sampling technique used to assess the quality of a batch of PCBs. Essentially, it defines the maximum allowable percentage of defective PCBs considered acceptable within a given sample size.
Categories: Board Parts / Components
Arduino
Arduino is an open-source electronics platform based on easy-to-use hardware and software. Based in Italy, the company manufactures microcontroller boards which can be programmed to interact with electronics or control devices. Arduino provides a simplified software environment based on the Wiring programming language, making it easy for beginners to learn programming concepts. You can write sketches (programs) in C or C++ language and upload them to the Arduino board to control its functions.
Categories: Board Parts / Components
Array
In the context of PCBA manufacturing, this refers to a systematic arrangement of identical electronic components on a PCB, typically in rows and columns. Arrays allow for compact and organized placement of components to better utilize board space. Moreover, arrays of passive components can determine filtering characteristics, power distribution, and signal integrity. Common types of arrays include LED arrays, ball grid arrays (BGAs), and programmable gate arrays (FPGAs).
Categories: Board Parts / Components
ASIC
An Application-Specific Integrated Circuit (ASIC) is a specialized type of computer chip designed and manufactured for a specific purpose. Unlike general-purpose microcontrollers or processors, ASICs are custom-built to perform a particular set of tasks within an electronic device. They offer optimized performance compared to off-the-shelf components, with multiple functionalities integrated onto a single chip. This can minimize the overall size of the PCB assembly and potentially reduce manufacturing costs. They may be used as mobile processors, wireless communication chips, or custom controllers.
Categories: Board Parts / Components
Axial Lead
An axial lead component is a type of electronic component with wire leads that extend axially (in a straight line) from the body of the component, along its longitudinal axis. This differentiates them from radial lead components where both leads are located close together on one side. These leads are typically used for insertion through holes drilled in a printed circuit board (PCB) for soldering and electrical connection.
Many passive components utilize axial leads including many resistors, capacitors, inductors, and diodes.
Categories: Board Parts / Components
Backplane
A backplane functions as the central interconnection hub for a system, essentially a printed circuit board (PCB) populated with standardized slots or connectors. These slots allow for the integration of various daughterboards, like memory modules, network cards, or storage drives. Backplanes offer exceptional scalability and are designed to facilitate high-bandwidth data transfer between connected daughterboards. Certain backplane configurations support hot-swapping, allowing for the replacement of daughterboards without powering down the entire system.
Categories: Board Parts / Components
BGA, Ball Grid Array
A Ball Grid Array (BGA) represents a surface-mount package for integrated circuits (ICs). Unlike traditional packages with leads, BGAs feature an array of tiny solder balls on the underside. These solder balls act as electrical connections between the IC and the printed circuit board (PCB).
BGAs can accommodate a significantly higher number of electrical connections compared to traditional packages with leads. The shorter connection paths offered by BGA solder balls contribute to improved electrical performance, particularly at high-frequencies. However, BGAs require precise soldering using specialized equipment and inspection of solder joints may be difficult. Additionally, BGA packages can generate significant heat due to their high density.
Categories: Board Parts / Components
Band-Pass Filter
A band-pass filter allows a specific range of frequencies to pass through while attenuating (weakening) all frequencies outside that range. Band-pass filters are used in various applications where you want to isolate a specific frequency band of interest, such as:
- Extracting the desired radio signal from an antenna in a radio receiver.
- Isolating the human voice range in a telephone communication system.
- Filtering specific color information for image processing.
Categories: Board Parts / Components
Band-Stop Filter
A band-stop filter, also known as a notch filter, does the opposite of a band-pass filter. It blocks (attenuates) a specific range of frequencies while allowing all other frequencies to pass through. Band-stop filters are used in various applications to eliminate unwanted noise or interference within a specific frequency range, such as:
- Removing power line hum from an audio signal.
- Eliminating interference from radio stations on another frequency band.
- Suppressing specific noise harmonics generated by electronic circuits.
Categories: Board Parts / Components
Bare Board
A bare board signifies a printed circuit board (PCB) in its unpopulated state. This essentially means the board lacks any electronic components like resistors, capacitors, or integrated circuits (ICs). It also doesn't have through-holes for component leads. Bare boards serve as the foundation upon which electronic components are soldered and assembled to create functional PCBAs. A bare board already features etched copper traces that create vital conductive pathways on the non-conductive substrate material, and may also include surface finishes to prevent corrosion and improve solderability.
Categories: Board Parts / Components
Base
In the context of PCBA manufacturing, "base" can have two related meanings, depending on the specific context. Here's a breakdown of both interpretations:
- Base Material:
This refers to the core structural element of a printed circuit board (PCB). It's the non-conductive material that provides mechanical support and serves as the foundation for the entire PCB assembly.
Common base materials include:
- FR4 (Flame Retardant 4): A composite material made of woven fiberglass cloth impregnated with epoxy resin. It offers a good balance of cost, performance, and fire resistance.
- Metal Core PCBs: These utilize aluminum or other metals as the base material for improved thermal conductivity, crucial for high-power applications.
- High-Frequency Laminates: Specialized materials designed for exceptional signal integrity at high frequencies, often used in RF and microwave circuits.
- Base Layer (for Multilayer PCBs):
- In multilayer PCBs, "base" can also refer to the bottom-most conductive layer of the board. This layer serves as the foundation for building the electrical connections within the PCB.
- Additional layers are laminated on top of the base layer, with each layer containing its own etched copper traces. Via holes connect these layers electrically, enabling complex circuit designs.
Note: The term "base" also has a broader meaning in electronics, referring to the electrode in a transistor that controls the current flow.
Categories: Board Parts / Components
Battery
Batteries are integrated components that provide portable power to electronic devices. They come in various shapes, sizes, and chemistries, each with specific characteristics that influence their suitability for different applications. Batteries store chemical energy and convert it into electrical energy to power electronic circuits. This electrical energy is typically delivered at a constant voltage level. Batteries may be non-rechargeable (alkaline or lithium coin) or rechargeable (Lithium-Ion or Lithium-Polymer). When choosing a battery, consider voltage and capacity requirements, physical size constraints, discharge characteristics, and any safety concerns.
Categories: Board Parts / Components
BJT, Bipolar Junction Transistor
A Bipolar Junction Transistor is a type of transistor that utilizes both electrons and holes (the absence of electrons) as charge carriers to regulate current flow. This is in contrast to another common transistor type, the Field-Effect Transistor (FET), which uses only one type of carrier. BJTs are essential components in various electronic circuits, enabling functions like amplification, switching, and signal processing.
A BJT is made from a thin layer of semiconductor material–typically silicon–sandwiched between two other regions of a different doping type. This creates an emitter(heavily doped region), a base (lightly doped region), and a collector(moderately doped region). By applying a small voltage to the base terminal, the BJT can control a much larger current flowing between the emitter and collector. BJTs are most commonly used as amplifiers, switches, and logic gates.
Categories: Board Parts / Components
Blind Via
A blind via is a specialized type of connection used in multilayer printed circuit boards (PCBs). It acts as a vertical electrical pathway that connects an outer layer of the PCB to one or more inner layers, but crucially, it doesn't extend all the way through to the opposite outer layer.
Blind vias are essential for creating high-density interconnect (HDI) PCBs with complex circuitry and many components. Blind vias are ideal for high-speed applications like RF circuits and digital communication systems due to their positive impact on signal integrity. Moreover, blind vias can help achieve consistent impedance characteristics within a PCB assembly.
Categories: Board Parts / Components
Board
A Printed Circuit Board (PCB). A PCB serves as the foundation for electronic circuits, containing etched copper traces on a non-conductive substrate material. Electronic components are soldered onto the board's surface to create a functional assembly.
Categories: Board Parts / Components
BQFP, Bumpered Quad Flat Package
A Bumpered Quad Flat Package (BQFP) is a specific type of surface-mount technology (SMT) package used for integrated circuits (ICs) in PCBA manufacturing. BQFPs have bumpers on the four package corners. These bumpers protrude slightly beyond the leads to provide physical protection as well as a buffer against vibrations that can bend or deform pins. BQFPs offer improved durability, faster assembly, and can accommodate a relatively high number of pins (from 84 to 196) to connect the IC to the PCB, making them suitable for complex circuits with numerous connections. In BQFP structures, pins are arranged closely, making the chip smaller and circuit design simpler, making it ideal for high-speed data transmission and high-power applications.
Categories: Board Parts / Components
Bridge Rectifier
A bridge rectifier is an electronic circuit component that efficiently converts alternating current (AC) into direct current (DC). It's a widely used and essential building block in various power supply circuits. It consists of four diodes connected in specific bridge configuration.
During the positive half cycle of the AC input voltage, two of the diodes become forward-biased (allowing current flow), while the other two are reverse-biased (blocking current flow). This allows positive DC current to flow through the output. During the negative half cycle of the AC input, the polarity is reversed. However, the bridge configuration automatically switches the functioning diodes. The two previously blocked diodes become forward-biased, and the previously conducting diodes become reverse-biased. This ensures that current always flows in the same direction at the output, resulting in pulsating DC (with positive peaks).
Bridge rectifiers may be used in power supplies, battery chargers, or AC adapters.
Categories: Board Parts / Components
Buried Via
A buried via represents a specialized type of plated connection used within multilayer printed circuit boards (PCBs). Unlike through-hole vias that pass through the entire board, and blind vias that connect outer layers to some inner layers, buried vias establish electrical pathways solely between inner layers of the PCB. They are not visible from the outer surfaces of the board.
Buried vias are formed during the PCB lamination process and connect designated points within the inner layer stack-up. They enable the creation of high-density interconnect (HDI) PCBs with more components in limited space. Buried vias contribute to better signal integrity by providing shooter, more direct electrical paths within the board as compared to traces routed on outer layers.
Categories: Board Parts / Components
Bus
Buses act as communication channels within a computer system, enabling data flow between various components. On PCBs (Printed Circuit Boards), these buses take physical form as traces that connect different integrated circuits (ICs). There are two main categories of buses to consider:
- Internal Buses (Data Buses): Responsible for data transfer within a single electronic device. They connect crucial components like the CPU, memory (RAM), and other internal ICs on the PCB, allowing them to exchange information.
- Examples: Memory bus (CPU to RAM), front-side bus (CPU to high-speed components), I/O bus (CPU to peripherals).
- External Buses (Expansion Buses): Facilitate communication between a device and external components like storage drives, displays, or network cards. They provide standardized connection points for these peripherals to interact with the system.
- Examples: USB, PCI Express (PCIe), SATA (Serial ATA), HDMI, Ethernet.
Categories: Board Parts / Components
C4, Controlled Collapse Chip Connection
Controlled Collapse Chip Connection (C4), also known as Flip Chip, signifies an innovative connection method for integrating integrated circuits (ICs) onto printed circuit boards (PCBs). Developed in the 1960s, this technology offers significant advantages for high-density and high-performance electronic assemblies.
The Flip-Chip process creates high-density chip connections. First, conductive bumps are deposited on the chip's top surface. Then, the chip is flipped and aligned with solder pads on a PCB. A reflow process melts the bumps, forming electrical connections. In some applications, underfill strengthens the joints.
C4/Flip Chip technology offers major benefits for PCB assembly. It enables denser connections due to smaller bumps, leading to miniaturization. The shorter connection path between chip and board improves electrical performance at high frequencies. Additionally, C4 connections are generally more reliable than traditional leaded packages.
Categories: Board Parts / Components
Cable
In PCBA manufacturing, a cable refers to an assembly of one or more insulated wires bundled together. These wires function as electrical conductors, transmitting electrical signals or power from one device to another. Cables carry electrical signals for data transmission, control purposes, or supplying power. There are many types of cables, including ribbon cables, coaxial cables, and power cables. Choose a cable with proper impedance characteristics and that is rated for the electrical load it will carry.
Categories: Board Parts / Components
Capacitor
Capacitors are fundamental passive electronic components that play a critical role in circuit functionality. Capacitors store energy in the form of an electrical field and can be charged by a voltage source and then discharge that stored energy when needed. Within a PCBA circuit, capacitors are used for decoupling, filtering, energy buffering, and tuning and resonance.
Ceramic capacitors are compact and offer high capacitance, making them ideal for filtering and smoothing power supplies. Electrolytic capacitors provide high capacitance in a small package, suitable for storing energy. Finally, film capacitors excel in stability and handling high voltages, making them perfect for filtering and timing circuits.
Categories: Board Parts / Components
Card
“Card” is another name for a Printed Circuit Board (PCB). A PCB serves as the foundation for electronic circuits, containing etched copper traces on a non-conductive substrate material. Electronic components are soldered onto the board's surface to create a functional assembly. You might hear someone refer to a PCB as a "card" in informal conversation.
“Card” could also refer to a type of daughterboard for added capabilities like a graphics card or network card.
Categories: Board Parts / Components
Card-edge Connector
A card-edge connector acts as a crucial bridge for electrical connections between a printed circuit board (PCB) and other components or systems. Card-edge connectors typically consist of a plastic housing with rows of metal contacts running along one edge. This edge mates directly with the edge of the PCB. Card-edge connectors provide compact and organized ways to connect multiple electrical signals, and enable easy insertion and removal of the PCB to facilitate maintenance, upgrades or testing. Such connectors are most commonly used in motherboards, backplanes, industrial control systems, and removable storage devices.
Categories: Board Parts / Components
Cathode
A cathode is an electrode that allows conventional current to leave a polarized device.
Categories: Board Parts / Components
CBGA, Ceramic Ball Grid Array
CBGA (Ceramic Ball Grid Array) is a specific type of surface-mount package for integrated circuits (ICs). CBGAs utilize a square or rectangular ceramic base instead of the typical plastic base found in many package types. Solder balls are attached in a grid-like pattern on the underside of the ceramic package. These solder balls create the electrical connections between the IC and the PCB during the reflow soldering process.
Categories: Board Parts / Components
CFP, Ceramic FlatPack
Ceramic FlatPack (CFP) is a type of integrated circuit (IC) package made from ceramic materials, known for its flat, rectangular shape and robustness. CFP packages are commonly used in military, aerospace, and high-reliability applications due to their excellent thermal performance, mechanical strength, and resistance to harsh environmental conditions.
Key features include:
- Thermal Performance: Ceramic materials provide superior heat dissipation compared to plastic packages.
- Hermetic Seal: CFPs often feature hermetic sealing, protecting the IC from moisture and contaminants.
- Reliability: The robust construction of CFPs ensures long-term reliability, even in extreme conditions.
CFPs typically have metal leads that extend from the sides of the package, allowing for surface-mount or through-hole mounting on a PCB.
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Chip
Chip (Die): In PCBA manufacturing, a chip, also known as a die, refers to a miniaturized circuit built on a silicon wafer using complex semiconductor fabrication processes. It integrates billions of microscopic transistors, resistors, capacitors, and other electronic components onto a tiny piece of silicon. However, a chip in this bare die format is not directly usable on a PCBA. It requires further processing, including packaging, to provide electrical connections for integration with the PCB.
Chip (Packaged): In the context of PCBA assembly, "chip" often refers to a packaged semiconductor device. This is the completed form of the die after undergoing encapsulation and lead attachment. The package protects the delicate circuitry and provides a robust interface for soldering the chip onto the PCB. Common package types include quad flat packages (QFP), ball grid arrays (BGAs), and small-outline integrated circuits (SOICs).
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COB, Chip on Board
In COB technology, miniaturization reigns supreme.Instead of bulky individual LED packages, multiple LED chips are directly mounted onto a PCB substrate. These chips are secured using an adhesive or wire bonding.
The telltale sign of COB on a PCB is often a black blob of epoxy resin on the board's surface, technically called a glob top. This encapsulates the LED chips and their wire bonds, providing protection from physical damage, moisture, and environmental contaminants. COB technology is often used in LED lighting, mobile devices, wearable electronics, and mass-produced toys.
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CSP, Chip Scale Package
Chip Scale Package (CSP) is a type of IC package that is nearly the same size as the semiconductor chip itself, providing a very compact form factor. They are ideal for modern, high-density applications. Key characteristics include:
- Size: CSPs are generally less than 1.2 times the size of the die, providing significant space savings.
- Performance: The short interconnects between the chip and the PCB improve electrical performance and reduce signal loss.
- Manufacturing: CSPs can be easily mounted using standard surface-mount technology (SMT) processes.
Examples of CSPs include Wafer Level Chip Scale Packages (WLCSP) and Ball Grid Arrays (BGAs), which use small solder balls for electrical connections.
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Circuit
A circuit is a closed path through which an electric current flows. It consists of various electrical components such as resistors, capacitors, inductors, diodes, transistors, and power sources. There are several types of circuits, including:
- Series Circuit: Components are connected end-to-end, with the same current flowing through each component.
- Parallel Circuit: Components are connected across common points, providing multiple paths for the current.
- Complex Circuit: A combination of series and parallel circuits, often found in practical electronic devices.
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Coating
Coating refers to the application of a protective layer over the components and circuitry to safeguard against environmental factors such as moisture, dust, chemicals, and mechanical damage. Common types of coatings include:
- Conformal Coating: A thin, protective polymer layer applied to the entire PCB assembly. It conforms to the board's contours, providing protection while allowing the board to dissipate heat.
- Encapsulation (Potting): Enclosing the entire assembly in a protective material, providing robust mechanical support and protection from harsh environments.
-Protective Lacquers and Varnishes: Applied to specific areas or the entire PCB to provide a barrier against moisture and contaminants.
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Collector
The collector is one of the three terminals of a bipolar junction transistor (BJT), along with the emitter and base. It is the terminal through which the majority of the charge carriers (electrons or holes) leave the transistor. When the transistor is in active mode, the collector current is controlled by the base current and is typically much larger than the base current. The collector is usually connected to the positive supply voltage in an NPN transistor or to the negative supply voltage in a PNP transistor. The ability to control a large current with a smaller one makes transistors useful for amplification and switching applications.
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Comparator
A comparator is an electronic device that compares two voltages or currents and outputs a digital signal indicating which is larger. Comparators are used in various applications, such as analog-to-digital converters, oscillators, level detection circuits, and decision-making circuits.
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Component
A component is an individual electronic device or part used in the construction of electronic circuits and systems. Components can be passive (resistors, capacitors, inductors) or active (transistors, diodes, integrated circuits). Proper selection and placement of components are crucial for achieving the intended performance and reliability of the circuit.
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Contact
A contact is a conductive part of an electrical connector that forms an electrical connection between two or more components. Contacts are used in various connectors, switches, and relay terminals to establish a reliable electrical path. They can be made from materials such as gold, silver, or copper, which have excellent conductivity and resistance to corrosion.
The quality of the contact determines the efficiency and stability of the connection. Contacts must be designed to handle the required current and voltage levels without significant degradation over time.
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Copper Tracks
Copper tracks, also known as traces, are conductive pathways on a PCBA that connect different components and carry electrical signals. The width and thickness of the copper tracks are designed based on the current-carrying requirements and thermal considerations. Proper design of copper tracks is essential for ensuring signal integrity, minimizing resistance, and avoiding issues such as overheating and crosstalk.
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Connector
A connector is an electromechanical device used to join electrical circuits together, providing a detachable interface between components or systems.Connectors are designed to ensure reliable and secure connections, with considerations for factors such as pin count, pitch, current rating, and environmental resistance. Common types include USB connectors, ribbon cable connectors, and board-to-board connectors.
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Countersink Holes
Countersink holes are conical holes in a PCBA, designed to allow the head of a countersunk screw to sit flush with or below the surface. They are used to mount the PCBA securely while ensuring that the screws do not protrude and cause mechanical or electrical issues.
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Counterbored Holes
Counterbored holes are cylindrical recesses in a PCBA, designed to allow the head of a socket-head or other non-countersunk screw to sit flush with or below the surface. The counterbore provides a flat-bottomed hole that accommodates the screw head, while the smaller diameter hole continues through the material for the screw shaft. They are used in PCB mounting to ensure secure fastening without protruding screw heads, which could interfere with components or cause mechanical stress.
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Crystal Oscillator
A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency. Crystal oscillators offer stable and precise frequencies, with little noise. They are used in timing and syncing clocks, microcontrollers, and communication systems.
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Cutout
A cutout refers to a section where material is removed from the PCBA to create an opening or void. Cutouts are used for various purposes, such as creating space for components that extend below the PCB, accommodating connectors, or reducing the board's weight.
They can also be used for thermal management by allowing airflow through the board. Cutouts must be carefully designed to maintain the structural integrity of the PCBA and to ensure that they do not interfere with the circuit's functionality. They are defined in the PCBA design layout and are implemented during the board's fabrication process.
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Daughterboard
A daughterboard, also known as a daughter card, is a secondary circuit board that is attached to and extends the functionality of the main motherboard or primary circuit board. Daughterboards are used to add additional features, capabilities, or interfaces to a system without modifying the main board.
They are connected to the motherboard through various connectors, such as edge connectors, pin headers, or sockets. Examples include graphics cards, sound cards, and expansion cards in computers. Daughterboards allow for modularity and easy upgrades, enabling systems to be customized for specific applications or expanded as needed.
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Device
A device is a component or piece of equipment that performs a specific function within an electronic system. Devices can range from simple passive components, like resistors and capacitors, to complex integrated circuits and microprocessors. Each device has a specific role in the overall operation of an electronic circuit, such as amplifying signals, switching, computing, or storing data.
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DIAC, Diode for Alternating Current
A DIAC (Diode for Alternating Current) is a bidirectional semiconductor device that conducts current only after its breakover voltage has been exceeded in either direction. DIACs are used primarily in triggering applications, such as in phase control circuits for dimming lights or controlling motor speed.
DIACs provide a controlled breakdown characteristic, allowing current to flow once the voltage across the DIAC exceeds a certain threshold. This characteristic makes them useful for controlling the triggering of TRIACs (Triode for Alternating Current), which are used in AC power control applications. DIACs help ensure smooth and reliable switching by providing a sharp transition from non-conducting to conducting states.
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Dielectric
A dielectric is an insulating material that does not conduct electric current but can support an electrostatic field, allowing it to store electrical energy. The dielectric constant (relative permittivity) of the material determines its ability to store electrical energy.
Dielectrics are used in various electronic components, such as capacitors, where they separate conductive plates and store electrical energy in the form of an electric field. In PCBA design, the substrate material (such as FR-4) is a dielectric. It provides insulation between the conductive copper layers. The material also affects the board's electrical traits, like impedance and signal speed.
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Digital Circuit
Digital circuits are electronic circuits characterized by their use of binary logic, where signals are either high (1) or low (0). They use logic gates (AND, OR, NOT, etc.), flip-flops, counters, and other digital components to perform operations like computation, data storage, and signal processing. Digital circuits form the basis of modern electronic systems, including computers, communication devices, and control systems.
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Diodes
A diode is a semiconductor device that allows current to flow in one direction only, blocking it in the opposite direction. Diodes are essential components in many electronic circuits, providing functions such as rectification, voltage regulation, signal demodulation, and protection against voltage spikes.
There are various types of diodes, each with specific characteristics and applications:
- Rectifier Diodes: Used in power supplies to convert AC to DC.
- Zener Diodes: Allow current to flow in reverse when a specific breakdown voltage is reached, used for voltage regulation.
- Light Emitting Diodes (LEDs): Emit light when current flows through them, used in displays and indicators.
- Schottky Diodes: Have low forward voltage drop and fast switching, used in high-speed and low-voltage applications.
- Photodiodes: Generate current when exposed to light, used in light detection and solar cells.
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Die
A die is a small block of semiconducting material on which a specific functional circuit is fabricated. It is a core component of an integrated circuit (IC). After the semiconductor manufacturing process, the wafer is cut into individual dies, each containing a specific circuit design, such as a microprocessor, memory chip, or sensor. These dies are then packaged to form ICs, which can be mounted onto PCBs. The packaging provides physical protection, electrical connections, and thermal dissipation. The quality and performance of the die are critical to the functionality of the final electronic component.
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DIP, Dual In-line Package
A Dual In-line Package (DIP) is a type of electronic component package with two parallel rows of pins extending perpendicularly from the package. DIPs are commonly used for through-hole mounting on PCBs. The pins can be inserted into holes on the PCB and soldered for a secure connection. DIPs are available in various sizes, typically defined by the number of pins (e.g., 8, 14, 16, 40 pins). DIPs are easy to handle and solder, making them suitable for prototyping and educational purposes.
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Discrete Component
A discrete component is an individual electronic component with a single function, such as a resistor, capacitor, inductor, diode, or transistor. Unlike integrated circuits (ICs), which combine multiple functions into a single package, discrete components perform specific, isolated tasks.
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DLCC, Dual Leadless Chip Carrier
A Dual Leadless Chip Carrier (DLCC) is a type of surface-mount packaging for ICs, characterized by its lack of leads (pins) extending from the package. DLCCs have metal pads or terminations on the bottom or sides of the package, which are soldered directly to the PCB. This type of package provides a compact footprint and improved thermal performance compared to traditional leaded packages. DLCCs are used in applications where space is limited, and high reliability is required, such as in aerospace, military, and industrial electronics.
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Double-sided PCB
A double-sided PCB is a printed circuit board with conductive copper traces on both the top and bottom surfaces. Double-sided PCBs allow for more complex circuit designs compared to single-sided PCBs, as components and traces can be placed on both sides of the board. Vias (plated holes) are used to create electrical connections between the two sides. They offer a good balance between complexity, cost, and manufacturability.
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DRAM, Dynamic Random Access Memory
Dynamic Random Access Memory (DRAM) is a type of volatile memory used in computers and other electronic devices to store data temporarily. DRAM stores each bit of data in a separate capacitor within an integrated circuit. Since capacitors leak charge over time, DRAM cells must be periodically refreshed to maintain the stored data, hence the term "dynamic."
DRAM is widely used as the main system memory in computers due to its high density, speed, and cost-effectiveness. However, it loses its data when power is removed, making it unsuitable for long-term storage.
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Dry Film Solder Mask
Dry film solder mask is a type of solder mask applied as a solid film that is laminated onto the PCB surface and then patterned using photolithography. The dry film solder mask process involves the following steps:
- Lamination: The dry film is laminated onto the PCB surface.
- Exposure: The film is exposed to ultraviolet (UV) light through a photomask, which defines the areas to be protected or exposed.
- Development: The unexposed areas are developed and washed away, leaving the desired solder mask pattern.
Dry film solder mask provides precise and consistent coverage, protecting the PCB from solder bridges, oxidation, and other contaminants. It is commonly used in high-precision and high-volume PCB manufacturing.
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Dummy Traces
Dummy traces are non-functional copper traces added to a PCB layout. Dummy traces do not carry electrical signals but serve important roles in PCB design:
- Copper Balance: Ensuring an even distribution of copper across the PCB to prevent warping and improve plating quality.
- Structural Support: Adding mechanical stability to the PCB, especially in areas with large copper-free spaces.
- Impedance Matching: Providing consistent impedance for high-speed signal traces by balancing the copper layout.
Dummy traces help achieve better manufacturing yields and improve the overall reliability and performance of the PCB.
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EEPROM, Electrically Erasable Programmable Read-Only Memory
EEPROM is a type of non-volatile memory that can be electrically erased and reprogrammed. EEPROM retains its data even when the power is turned off, making it suitable for storing configuration settings, calibration data, and other information that must persist between power cycles. Unlike other types of read-only memory, EEPROM can be reprogrammed in-circuit without the need for special equipment.
Key characteristics of EEPROM include:
- Byte-Addressability: Data can be read and written at the byte level, allowing for fine-grained control and modification.
- Reusability: EEPROMs can endure many write/erase cycles (typically in the range of hundreds of thousands to millions).
- Flexibility: Used in various applications, including microcontrollers, where parameters need to be adjusted or updated after manufacturing.
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Edge Connector
An edge connector is a type of electrical connector that consists of a series of conductive pads or traces along the edge of a PCBA. Edge connectors are used to interface a PCBA with external devices or other circuit boards, providing a reliable and detachable connection. They are commonly found in applications such as expansion cards (e.g., PCI, ISA) and memory modules. Key features include:
- High Density: Allowing multiple connections in a compact space.
- Ease of Use: Facilitating easy insertion and removal without soldering.
- Durability: Designed to withstand repeated insertion and removal cycles.
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Edge Plating
Edge plating, also known as castellations or half-holes, refers to the process of applying a layer of conductive material (usually copper) along the edges or around the perimeter of a PCBA. It is commonly used for:
- Improving Connectivity: Providing robust electrical connections along the edge of the board, particularly for edge connectors.
- Mechanical Strength: Adding structural integrity to the edges of the PCB, reducing the risk of damage during handling or insertion.
- Shielding: Enhancing EMI shielding by creating a continuous conductive path around the PCBA.
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Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. electromagnets consist of a coil of wire, typically wound around a core of ferromagnetic material, such as iron. When an electric current flows through the coil, it generates a magnetic field around the wire. The strength of the magnetic field can be controlled by varying the amount of electric current flowing through the coil.
Electromechanical Components
Electromechanical components are devices that combine electrical and mechanical processes to perform a specific function. These components often involve systems where electrical signals control mechanical movement or where mechanical action generates electrical signals.
Common examples include:
- Relays: Electrically operated switches that use an electromagnet to mechanically operate a switch.
- Solenoids: Devices that convert electrical energy into linear motion, often used in locking mechanisms and valve control.
- Motors: Convert electrical energy into rotational motion, used in a wide range of applications from household appliances to industrial machinery.
- Switches: Mechanical devices that open or close electrical circuits, activated by manual operation or other mechanical means.
- Electromechanical components are essential in systems where electrical signals control mechanical movement or where mechanical action generates electrical signals.
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Emitter
The emitter is one of the three terminals of a bipolar junction transistor (BJT), the other two being the base and the collector. The emitter is the terminal through which charge carriers (electrons in an NPN transistor or holes in a PNP transistor) enter the base region. The emitter is typically heavily doped to supply a high concentration of charge carriers. In an active transistor, the current flowing from the emitter to the collector is controlled by the current flowing into the base.
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Enclosure
An enclosure in electronics refers to a protective casing that houses electronic components and assemblies. Enclosures are designed to protect PCBAs from dust, moisture, mechanical damage, and electromagnetic interference (EMI). They also provide structural support and can be designed with features like cooling vents, mounting points, and connectors.
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Epoxy Resin
Epoxy resin is a type of polymer material commonly used as an adhesive, coating, or encapsulant in electronics and PCBA manufacturing. Epoxy resins are known for their excellent mechanical properties, chemical resistance, and strong adhesion. In PCBA manufacturing, epoxy resin is used for:
- PCB Laminate Material: Forming the substrate (e.g., FR-4) that supports the copper traces.
- Encapsulation: Protecting electronic components from environmental damage and mechanical stress.
- Adhesives: Bonding components and assemblies together.
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EPROM, Erasable Programmable Read-Only Memory
EPROM is a type of non-volatile memory that can be erased by exposing it to ultraviolet (UV) light and reprogrammed. EPROM retains data even when power is removed, making it useful for storing firmware and other data that need to be preserved. The erasing process involves exposing the memory chip to UV light through a transparent quartz window on the package, which resets the stored data. Once erased, the EPROM can be reprogrammed using a special programming device. EPROMs were widely used before the advent of more convenient electrically erasable memory types (EEPROM and Flash memory).
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External Layer
The external layer refers to the outermost conductive layers on a multilayer PCBA, typically containing signal traces, pads, and other electrical connections. The external layers are exposed to the environment and often house the majority of the components and interconnections.
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FBGA, Fine-pitch Ball Grid Array
FBGA is a type of surface-mount packaging for integrated circuits. It has an array of solder balls on the underside of the package. The balls are closer together than those in standard BGA packages. FBGA packages are for devices that need high-density interconnections.
They are common in memory chips (e.g., DDR SDRAM), microprocessors, and other high-performance ICs. The key characteristics of FBGA are:
- High Pin Count: Allows for more connections in a smaller area, making it suitable for complex and high-speed circuits.
- Fine Pitch: The spacing between the solder balls is smaller than in standard BGAs, enabling higher density and smaller package sizes.
- Improved Performance: The shorter interconnect paths reduce signal latency and improve electrical performance, making FBGA suitable for high-frequency applications.
FBGA packages are mounted onto PCBs using automated assembly processes, providing reliable and robust connections for advanced electronic systems.
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Ferrite Bead
A ferrite bead is a passive electronic component that suppresses high-frequency noise in electronic circuits by dissipating it as heat. Ferrite beads are made from ferrite material, which is a type of ceramic compound with magnetic properties.
They are commonly used in power supply lines and signal lines to filter out unwanted noise and prevent electromagnetic interference (EMI). Key features and applications include:
- Noise Suppression: Ferrite beads act as low-pass filters, allowing low-frequency signals to pass while attenuating high-frequency noise.
- EMI Reduction: Used to reduce electromagnetic interference in sensitive circuits, improving overall signal integrity.
- Placement: Often found on power lines entering a PCB or near noise-sensitive components.
Ferrite beads are simple and effective components for managing EMI and improving the performance of electronic circuits.
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Ferrite Core Inductor
A ferrite core inductor is an inductor that uses a core made of ferrite material to enhance its inductance and performance. Inductors are passive components that store energy in a magnetic field when electrical current flows through them. The ferrite core increases the inductance and efficiency of the inductor by providing a higher magnetic permeability than air or other materials.
Key features and applications include:
- High Inductance: Ferrite cores enable higher inductance values in a smaller size compared to air-core inductors.
- Energy Storage: Used in power supplies, DC-DC converters, and other applications where energy storage and filtering are required.
- Noise Filtering: Commonly used in EMI filters to block high-frequency noise and prevent it from entering sensitive parts of the circuit.
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FET, Field-Effect Transistor
A Field-Effect Transistor (FET) is a type of transistor that controls the flow of electrical current by applying a voltage to an electric field. They have three terminals: the gate, the drain, and the source. The operation of a FET is based on the voltage applied to the gate, which controls the current flowing from the drain to the source.
There are two main types of FETs:
- JFET (Junction Field-Effect Transistor): Uses a junction to control the current. It has a high input impedance and is commonly used in analog circuits.
- MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor): Uses an insulated gate to control the current. It is widely used in digital and analog circuits due to its high input impedance and fast switching capabilities. MOSFETs come in two types: n-channel and p-channel, depending on the type of charge carriers.
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FFC, Flat Flexible Cable
FFC is a type of cable with multiple flat conductors arranged parallel to each other, encapsulated in a flexible plastic film. FFCs are used to connect electronic components in compact and flexible configurations. They offer several advantages:
- Flexibility: Can be bent and folded to fit into tight spaces, making them ideal for applications like laptops, printers, and other portable devices.
- Lightweight: Their thin and flat design reduces the weight of the overall assembly.
- Ease of Use: Simple to install and connect, often used with Zero Insertion Force (ZIF) connectors.
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Finger
A finger, also known as a gold finger, is a gold-plated contact point on the edge of a PCBA. Gold fingers are used to create reliable, low-resistance connections between the PCB and a mating connector. They are commonly found in expansion cards, memory modules, and other plug-in boards.
Key features include:
- Gold Plating: Provides excellent conductivity and resistance to corrosion, ensuring a durable and stable connection.
- Edge Connector Compatibility: Designed to fit into edge connectors, allowing for easy insertion and removal without soldering.
Gold fingers are crucial for creating modular and interchangeable electronic systems, enabling easy upgrades and replacements.
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Flex Circuit
A flex circuit, or flexible printed circuit (FPC), is a type of PCB that can bend and flex while maintaining its electrical performance. Flex circuits are made from flexible materials such as polyimide or polyester, with copper traces laminated onto the substrate. They offer several benefits:
- Flexibility: Can be folded, bent, and twisted to fit into complex shapes and tight spaces, making them ideal for compact and portable devices.
- Reduced Weight and Space: Thinner and lighter than traditional rigid PCBs, contributing to the miniaturization of electronic devices.
- Durability: Capable of withstanding repeated flexing and bending without breaking.
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Flip-Chip
Flip-chip is a method of mounting semiconductor devices directly onto a PCB or substrate, with the active side of the chip facing downwards. First, solder bumps are added to the semiconductor wafer's pads. Then, the chip is placed upside down, aligning the bumps with the PCB's pads. When heated, the solder melts, creating a strong connection.
Key advantages include:
- Reduced Signal Path: Shorter interconnects improve electrical performance and reduce signal delay.
- Increased Density: Allows for more compact and efficient packaging of integrated circuits.
- Improved Thermal Performance: Direct connection to the substrate helps dissipate heat more effectively.
Flip-chip technology is commonly used in high-performance applications such as microprocessors, graphics processors, and high-frequency devices.
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Flip Flop
A flip-flop is a bistable electronic circuit that has two stable states. Flip-flops are fundamental building blocks in digital electronics, used for storage, data transfer, and synchronization. They are typically constructed using logic gates and can be triggered by changes in input signals or clock pulses.
There are several types of flip-flops, including:
- SR (Set-Reset) Flip-Flop: Simple flip-flop with set and reset inputs.
- D (Data or Delay) Flip-Flop: Captures and stores the input data on the rising or falling edge of a clock signal.
- JK Flip-Flop: A versatile flip-flop with toggle functionality, providing more control options than SR flip-flops.
- T (Toggle) Flip-Flop: Toggles its state on each clock pulse.
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Flux
Flux is a chemical cleaning agent used in soldering processes to remove oxidation from metal surfaces and improve the wetting of solder. There are different types of flux, including rosin-based, water-soluble, and no-clean fluxes. The choice of flux depends on the specific application and requirements of the soldering process.
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FPGA, Field-Programmable Gate Array
FPGA is an integrated circuit that can be configured by the user after manufacturing to perform specific logic functions. FPGAs are highly flexible and versatile devices used in a wide range of applications, from simple logic implementations to complex digital systems.
Key features of FPGAs include:
- Reconfigurability: FPGAs can be programmed and reprogrammed to implement different logic functions and designs, allowing for iterative development and updates.
- Parallel Processing: FPGAs can execute multiple operations simultaneously, making them ideal for high-performance computing tasks.
- Customizability: Users can create custom digital circuits tailored to specific applications, such as signal processing, data encryption, and control systems.
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FR4
FR4 is a grade of flame-retardant fiberglass-reinforced epoxy laminate material used as a substrate for printed circuit boards (PCBs). R4 is one of the most common materials used in PCB manufacturing due to its excellent mechanical strength, electrical insulation properties, and resistance to moisture.
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Full Wave Rectifier
A full-wave rectifier is an electronic circuit that converts an alternating current (AC) input into a direct current (DC) output by using both halves of the AC waveform. Full-wave rectifiers are more efficient than half-wave rectifiers, as they utilize both the positive and negative halves of the AC cycle. There are two common types of full-wave rectifier circuits:
- Center-Tap Full-Wave Rectifier: Uses a center-tapped transformer and two diodes. The center tap provides a reference point, and the diodes rectify both halves of the AC waveform.
- Bridge Rectifier: Uses four diodes arranged in a bridge configuration to rectify both halves of the AC input without the need for a center-tapped transformer.
The output of a full-wave rectifier is a pulsating DC voltage, which can be further smoothed using filter capacitors. Full-wave rectifiers are commonly used in power supply circuits to provide a stable DC voltage from an AC source.
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Fuse
A fuse is a protective electrical device that interrupts the flow of current in a circuit when the current exceeds a predetermined level, preventing damage. It is crucial for protecting devices from overheating, damage, or fire.
Key features of fuses include:
- Current Rating: The maximum current the fuse can carry without blowing. Exceeding this current will cause the fuse to melt and open the circuit.
- Voltage Rating: The maximum voltage the fuse can safely interrupt.
- Blow Characteristics: Fuses can be fast-blow or slow-blow, depending on how quickly they respond to overcurrent conditions. Fast-blow fuses respond quickly to sudden surges, while slow-blow fuses tolerate short-duration inrush currents.
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Gold Fingers
Gold fingers are gold-plated connectors on the edge of a PCBA that allow it to interface with other boards or devices, such as in edge connectors. Gold fingers are essential for creating reliable, low-resistance connections between PCBAs and connectors. They are typically used in applications like expansion cards (e.g., PCI, AGP) and memory modules. The process of creating gold fingers involves plating the edge connectors with a layer of gold, often over a layer of nickel, to enhance durability and conductivity.
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GPU, Graphics Processing Unit
A GPU is a specialized electronic circuit designed to accelerate the processing of images and video for display. GPUs are optimized for handling complex mathematical and geometric calculations necessary for rendering graphics. They are used in a variety of applications, including, gaming and General-Purpose Computing (GPGPU).
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Gull Wing
Gull wing refers to a type of surface-mount lead configuration for electronic components. It has leads that extend outward from the body of the component and then bend downward, resembling the shape of a gull's wings.
Key features and advantages include:
- Ease of Inspection: The exposed leads make it easy to inspect solder joints for quality and reliability.
- Self-Alignment: During reflow soldering, the solder's surface tension helps to align the component leads with the PCB pads. This ensures accurate placement.
- Reliable Solder Joints: The bent leads provide more area for soldering. This makes the solder joints strong and reliable.
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Half Wave Rectifier
A half-wave rectifier uses a single diode to conduct current during only one half of the AC cycle (either the positive or negative half, depending on the diode's orientation). The result is a pulsating DC output that has a lower average voltage compared to a full-wave rectifier. It is used in applications where the power requirements are low and ripple can be tolerated, such as in small power supplies and signal demodulation.
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Hard Gold
Hard gold is a type of gold plating that's durable and resistant to wear. It's an alloy of gold with other elements like cobalt or nickel. This makes it ideal for contacts and connectors that are frequently connected and disconnected. Hard gold is thicker than soft gold, so it's more durable, but also more expensive.
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HDI, High-Density Interconnector
HDI is a type of PCB technology that uses fine features, such as microvias, blind and buried vias, and high wiring density, to achieve greater circuit density. HDI PCBs are compact, lightweight, and high-performance. They meet modern electronics' demands for miniaturization and functionality.
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HDMI, High-Definition Multimedia Interface
HDMI is a proprietary audio/video interface used for transmitting uncompressed digital data between devices. HDMI is widely used for connecting high-definition audio and video devices, such as TVs, monitors, gaming consoles, and media players. HDMI also supports various advanced features, such as HDMI-CEC (Consumer Electronics Control) for controlling multiple devices with a single remote, and HDMI ARC (Audio Return Channel) for simplifying audio connections between TVs and audio systems.
Categories: Board Parts / Components
Header
A header is an electrical connector with rows of pins. They come in various configurations. These include single-row and double-row. They can have different pin pitches (spacing between pins). A header connects wires, cables, or components to a PCBA. It makes connecting and disconnecting easy. This helps with modular designs and quick upgrades or repairs.
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Heat Sink
A heat sink is a passive cooling device. It dissipates heat made by electronic parts, such as processors and transistors, and it stops them from overheating. They are usually made of materials with high conductivity, such as aluminum or copper. They have fins or other structures to increase the surface area, which increases heat dissipation. Heat sinks can be attached to components using thermal adhesive, screws, or clips. They often use thermal interface materials (TIMs) like thermal paste or pads to improve contact.
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Hybrid
A hybrid refers to a circuit or device that combines different types of components or technologies to achieve specific functionalities or performance characteristics. It combines the strengths of different technologies. This mix achieves better performance. It allows for compact and efficient design by integrating many functions into a single module.
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IC, Integrated Circuit
An Integrated Circuit (IC) is a semiconductor device that consists of multiple interconnected electronic components, such as transistors, diodes, resistors, and capacitors, fabricated onto a single piece of semiconductor material, typically silicon. ICs are fundamental building blocks in modern electronics, enabling the development of compact, high-performance electronic devices.
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Inductors
An inductor is a passive electronic component that stores energy in a magnetic field when electrical current flows through it. The stored energy is released when the current through the inductor changes. Inductors are typically made of a coil of wire wound around a core, which can be air, iron, or ferrite.
Inductors are characterized by their inductance, measured in henries (H), which indicates the amount of magnetic flux generated per unit of current. The value of inductance depends on factors such as the number of turns in the coil, the core material, and the physical dimensions of the inductor.
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Interface
An interface in electronics refers to a shared boundary across which two or more separate components or systems exchange information, signals, or power. They can be categorized into several types:
- Hardware Interfaces: Physical connections, such as USB ports, HDMI connectors, and GPIO pins, that allow devices to connect and communicate.
- Software Interfaces: Protocols and APIs (Application Programming Interfaces) that define how software components interact and exchange data.
- User Interfaces: Means through which users interact with electronic devices, including graphical user interfaces (GUIs), command-line interfaces (CLIs), and touchscreens.
Interfaces play a crucial role in ensuring compatibility and functionality between different components, devices, and systems. They define the rules and standards for data exchange, enabling seamless integration and operation.
Categories: Board Parts / Components
Internal Layers
Internal layers refer to the layers that are embedded within the multilayer structure of a PCBA. Internal layers serve various purposes:
- Power and Ground Planes: Dedicated layers for distributing power and providing a common ground, which helps in reducing noise and improving signal integrity.
- Signal Layers: Layers that carry traces for routing signals between components. These layers can be used for high-speed signal routing, minimizing crosstalk and interference.
- Heat Dissipation: Copper layers can help dissipate heat generated by components, improving thermal management.
Categories: Board Parts / Components
Interstitial Via Hole
An interstitial via hole is a type of via in a multilayer PCB that connects internal layers without passing through the entire thickness of the board. There are two main types: Buried Vias and Blind Vias. Buried vias connect internal layers but do not extend to the outer layers. They are completely encapsulated within the PCBA. Blind vias connect an outer layer to one or more internal layers but do not pass through the entire board. They are visible on one surface of the PCBA.
Interstitial vias offer several advantages:
- Increased Routing Density: Allow for more complex and compact designs by providing additional routing paths within the internal layers.
- Improved Signal Integrity: Reduce the length of signal paths and minimize the chances of signal degradation and interference.
- Space Optimization: Free up space on the outer layers for component placement and routing by moving some connections to the internal layers.
Categories: Board Parts / Components
J-Lead
J-lead refers to a type of surface-mount lead configuration for electronic components where the leads are bent into a "J" shape. This shape helps align the component during soldering and provides good mechanical support and stress relief for solder joints. J-lead packages are commonly used in devices such as Small Outline J-lead (SOJ) packages and Plastic Leaded Chip Carrier (PLCC) packages. They are often found in memory chips, microcontrollers, and other integrated circuits.
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Jack
A jack is an electrical connector used as a receptacle or socket for plugging in a corresponding plug, enabling the connection of cables and electronic devices. Jacks come in various sizes and types, each for a different purpose. For example, there are audio, power, and network jacks.
Categories: Board Parts / Components
JFET, Junction Field-Effect Transistor
JFETs are voltage-controlled field-effect transistors used for switching and amplification. They have three terminals: the source, the drain, and the gate. The current flow between the source and drain terminals is controlled by a voltage applied to the gate terminal.
Key characteristics and applications include:
- High Input Impedance: JFETs have very high input impedance, making them suitable for use in amplifiers and buffers where minimal loading of the preceding circuit is required.
- Low Noise: JFETs generate less noise compared to bipolar junction transistors (BJTs), making them ideal for low-noise amplifier applications.
- Types: There are two types of JFETs: n-channel and p-channel. N-channel JFETs have a negative gate-source voltage to control the current, while p-channel JFETs have a positive gate-source voltage.
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Jumper
A jumper is a short length of conductor used to close, open, or bypass part of an electrical circuit, often for configuration purposes. Jumpers are typically used on PCBs and other electronic assemblies to allow for easy configuration and customization of circuits. They can be found in the form of:
- Jumper Wires: Short wires used to make temporary connections between two points on a PCB, often used in prototyping and testing.
- Jumper Blocks: Small connectors that fit over two or more pins on a header, creating a bridge between them. Jumper blocks are commonly used on motherboards and other PCBs to select settings, such as enabling or disabling features, setting voltage levels, or configuring device modes.
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Junction
A junction refers to the region where two different types of semiconductor materials (n-type and p-type) come into contact within a semiconductor device. The behavior of the junction under different biasing conditions (forward or reverse) determines the operation of the device, such as allowing or blocking current flow.
Key types of junctions include:
- PN Junction: Formed by the contact between p-type and n-type semiconductor materials. It is the fundamental building block of many semiconductor devices, including diodes and transistors.
- Schottky Junction: Formed between a metal and a semiconductor. It is used in Schottky diodes and certain types of transistors.
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Junction Diode
A junction diode is a semiconductor device that allows current to flow in one direction while blocking it in the opposite direction, formed by a PN junction. Junction diodes are the simplest type of semiconductor device and are used in a wide range of applications including rectification, clamping and clipping. Key characteristics and functions include:
- Forward Bias: When the anode (p-type) is connected to a positive voltage relative to the cathode (n-type), the diode conducts current.
- Reverse Bias: When the anode is connected to a negative voltage relative to the cathode, the diode blocks current, except for a small leakage current.
Specialized types of junction diodes include Zener diodes (for voltage regulation), LEDs (for light emission), and photodiodes (for light detection).
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Laminate
A laminate is a substrate material that forms the base of the PCBA. The most common type of PCBA laminate is FR4, which is a fiberglass-reinforced epoxy laminate. The laminate provides a rigid foundation for mounting and interconnecting electronic components. It ensures electrical isolation between different conductive layers and traces. It also dissipates heat generated by electronic components.
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Laser
Laser stands for Light Amplification by Stimulated Emission of Radiation. It is a device that emits a highly concentrated and coherent beam of light. Lasers have various applications in electronics and PCB manufacturing, including:
- Drilling: High-precision drilling of microvias and through-holes in PCBs.
- Cutting: Precision cutting and shaping of PCB substrates.
- Etching: Removing material to create patterns for circuit traces and other features.
- Marking: Adding labels, identifiers, or barcodes to PCBs and components.
The precision and control offered by lasers make them indispensable tools in modern electronics manufacturing, enabling the production of complex and high-density PCBs.
Categories: Board Parts / Components
Layers
Layers refer to the individual planes of conductive material, dielectric material, or both that are stacked together to form a multilayer PCBA. Layers in a PCBA are categorized into several types based on their function:
- Signal Layers: Carry electrical signals between components. These can be outer layers (top and bottom) or internal layers.
- Power and Ground Planes: Dedicated layers for distributing power (Vcc) and providing a common ground (GND) throughout the PCBA. These planes help reduce noise and improve signal integrity.
- Solder Mask: A protective layer applied over the conductive traces to prevent short circuits, corrosion, and mechanical damage. It also defines the areas for soldering components.
The number of layers in a PCBA depends on the complexity of the design, with common configurations ranging from single-layer boards to multi-layer boards with 4, 6, 8, or more layers.
Categories: Board Parts / Components
Lead
A lead is an electrical connection or terminal that extends from an electronic component, used to connect the component to a PCBA. Common types of leads include:
- Through-Hole Leads: Extend through holes in the PCBA and are soldered on the opposite side. Commonly used in components like resistors, capacitors, and DIP (Dual In-line Package) ICs.
- Surface-Mount Leads: Attach directly to the surface of the PCBA. Examples include gull-wing leads (bent outward and downward), J-leads (bent underneath the component), and flat leads (lying flat against the PCBA).
- Axial and Radial Leads: Found in passive components like resistors and capacitors. Axial leads extend from both ends of the component, while radial leads extend from one side.
Categories: Board Parts / Components
LCC, Leadless Chip Carrier
A Leadless Chip Carrier (LCC) is a type of surface-mount integrated circuit package that has no external leads extending from the package. Instead, it has metal pads or terminations on the bottom or sides of the package that make contact with the PCBA pads during soldering. Key features include:
- Compact Size: The absence of leads allows for a smaller package size, making LCCs suitable for high-density and compact designs.
- Improved Performance: The reduced parasitic inductance and capacitance from the lack of leads can enhance high-frequency performance.
Categories: Board Parts / Components
LED, Light Emitting Diode
A Light Emitting Diode (LED) is a semiconductor device that emits light when an electric current passes through it. LEDs operate by electroluminescence, where electrons recombine with holes in the semiconductor material, releasing energy in the form of photons (light). The color of the emitted light depends on the materials used in the LED. LEDs are widely used in various applications due to their energy efficiency, long lifespan, and versatility.
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LGA, Land Grid Array
A Land Grid Array (LGA) is a type of surface-mount packaging for integrated circuits where the electrical contacts are arranged as a grid of flat lands on the bottom of the package. LGA packages are designed to connect to corresponding pads on the PCB without the need for soldered leads. The flat contacts on the package make it easier to achieve good thermal and electrical performance, essential for modern high-speed and high-power applications. The grid layout allows for a high number of connections in a compact area, making LGA suitable for high-performance and high-pin-count devices.
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Logic Circuits
Logic circuits are electrical circuits that perform logical operations on one or more input signals to produce an output signal based on predefined rules. Logic circuits form the basis of digital electronics, enabling the processing and manipulation of binary data (0s and 1s). They are composed of interconnected logic gates that implement specific logical functions such as AND, OR, NOT, NAND, NOR, XOR, and XNOR.
There are two main types of logic circuits:
- Combinational Logic Circuits: The output depends solely on the current inputs. Examples include adders, multiplexers, and decoders.
- Sequential Logic Circuits: The output depends on both the current inputs and the previous states (history) of the circuit. Examples include flip-flops, counters, and shift registers.
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Logic Device
A logic device is an integrated circuit that performs digital logic functions. Some logic devices can be programmed by the user. For example, programmable logic devices (PLDs), and field-programmable gate arrays (FPGAs). Others are pre-designed to perform standard logic functions, like logic gates and counters.
Categories: Board Parts / Components
Logic Gate
A logic gate is a basic building block of digital circuits that performs a simple logical operation on one or more binary input signals to produce a single binary output signal.
The most common logic gates include:
- AND Gate: Outputs 1 if all inputs are 1; otherwise, outputs 0.
- OR Gate: Outputs 1 if at least one input is 1; otherwise, outputs 0.
- NOT Gate (Inverter): Outputs the opposite (complement) of the input.
- NAND Gate: Outputs 0 if all inputs are 1; otherwise, outputs 1 (inverse of AND gate).
- NOR Gate: Outputs 0 if at least one input is 1; otherwise, outputs 1 (inverse of OR gate).
- XOR Gate (Exclusive OR): Outputs 1 if the number of 1 inputs is odd; otherwise, outputs 0.
- XNOR Gate (Exclusive NOR): Outputs 1 if the number of 1 inputs is even; otherwise, outputs 0 (inverse of XOR gate).
Categories: Board Parts / Components
MCM, Multichip Module
MCM is an electronic assembly that contains multiple integrated circuits (ICs) or semiconductor dies, packaged together to function as a single component. MCMs provide a compact and high-performance solution for complex electronic systems. They are used in applications where high performance, miniaturization, and reliability are critical, such as in aerospace, telecommunications, medical devices, and high-end computing systems.
Categories: Board Parts / Components
MCU, Microcontroller Unit
A Microcontroller Unit (MCU) is a compact integrated circuit designed to govern a specific operation in an embedded system. It typically includes a processor, memory, and input/output (I/O) peripherals on a single chip.
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Membrane Switch
A membrane switch is a type of user interface device that uses pressure pads to open or close electrical circuits, typically consisting of multiple layers of flexible materials. Membrane switches are widely used in various electronic devices for their reliability, low profile, and ease of customization.
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Metal Oxide Resistor
A metal oxide resistor is a fixed resistor that uses metal oxides as the resistive element to provide a stable and reliable resistance value. It is made by depositing a metal oxide film (such as tin oxide) onto a ceramic substrate. The film is then etched to create a precise resistance value. It offers excellent temperature coefficient, meaning the resistance value changes very little with temperature variations. It is also capable of handling higher power levels compared to carbon film or metal film resistors.
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MIC
A microphone is a device that converts sound waves into electrical signals for recording or amplification. Common types include:
- Dynamic Microphones: Use a diaphragm attached to a coil of wire placed within a magnetic field. Sound waves cause the diaphragm to move, inducing a current in the coil.
- Condenser Microphones: Use a diaphragm placed close to a backplate, forming a capacitor. Sound waves change the distance between the diaphragm and the backplate, altering the capacitance and creating an electrical signal. They require an external power source, usually provided by phantom power.
- Electret Microphones: A type of condenser microphone that uses a permanently charged material, making them smaller and more convenient for portable devices.
Categories: Board Parts / Components
Micro Ball Grid Array
A Micro Ball Grid Array (Micro BGA) is a type of surface-mount packaging for integrated circuits that uses an array of tiny solder balls on the underside of the package to make electrical connections to the PCB. Micro BGAs are a miniaturized version of the traditional BGA, designed for high-density applications where space is limited.
Key features and applications include:
- Compact Size: The small size of the solder balls and the close spacing (pitch) between them allow for a high number of connections in a compact footprint.
- Improved Performance: Shorter interconnects between the IC and the PCBA reduce signal inductance and capacitance, improving electrical performance and allowing for higher operating frequencies.
- Heat Dissipation: The array of solder balls provides good thermal performance, helping to dissipate heat generated by the IC.
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Microvia
A microvia is a very small-diameter via, typically less than 150 micrometers (µm) in diameter, used to create electrical connections between layers in a multilayer PCBA. Microvias are essential for high-density interconnect (HDI) PCBAs, allowing for more compact and complex designs. They provide several advantages over traditional vias:
- Space Efficiency: Microvias enable higher component density and closer placement of traces, making them ideal for compact electronic devices.
- Improved Performance: The smaller size of microvias reduces parasitic capacitance and inductance, enhancing signal integrity and allowing for higher frequency operation.
- Versatility: Microvias can be used as blind vias (connecting an outer layer to an inner layer) or buried vias (connecting inner layers without reaching the outer layers).
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Motherboard
A motherboard is the main printed circuit board (PCB) in a computer or other complex electronic system, providing the primary platform for communication between the system's various components.
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Mounting Hole
A mounting hole is a hole in a PCB or other electronic assembly designed to accommodate a screw, bolt, or other fastener for securing the board or component to a chassis, enclosure, or another surface.
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MOV, Metal Oxide Varistor
A MOV is a variable resistor that protects electronic circuits by clamping voltage spikes and surges. MOVs are made of a ceramic mass of zinc oxide particles, which are sandwiched between two metal plates. When exposed to high voltage transients, the resistance of the MOV decreases sharply, allowing it to conduct current and absorb the surge energy.
Key features include:
- Surge Protection: MOVs are widely used in surge protectors, power strips, and other devices to protect sensitive electronics from voltage spikes caused by lightning, power surges, and other transient events.
- Non-Linear Resistance: The resistance of an MOV changes dramatically with applied voltage, providing effective clamping of voltage spikes.
- Reliability: MOVs can handle multiple transient events, though their effectiveness may degrade over time with repeated exposure to high-energy surges.
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Multilayer PCB
A multilayer PCB is a printed circuit board composed of multiple layers of conductive and insulating materials, stacked and laminated together to form a single board. Multilayer PCBs enable the integration of complex and high-density circuitry within a compact form factor.
Advantages of multilayer PCBs include:
- Increased Circuit Density: By stacking multiple layers, multilayer PCBs allow for more interconnections and components within a smaller footprint, making them ideal for complex electronic devices.
- Improved Electrical Performance: Multilayer designs provide better control over signal integrity, impedance, and electromagnetic interference (EMI) through the use of dedicated power and ground planes.
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Net
Nets are used to define the electrical connectivity between different components on a PCB. Each net corresponds to a specific signal or power connection, such as Vcc, GND, or signal lines. Key aspects include:
- Schematic Representation: Nets are shown in schematic diagrams as lines connecting component pins, indicating which pins should be electrically connected on the PCB.
- PCB Layout: In the PCB layout process, nets guide the placement of traces and vias to ensure proper electrical connections are made according to the schematic.
- Netlist: A netlist is a text file generated from the schematic that lists all the nets and their associated component pins, serving as a reference for PCB layout and manufacturing.
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Node
A node is a point in a circuit where two or more components are electrically connected.
Categories: Board Parts / Components
NPN Transistor
An NPN transistor is a type of bipolar junction transistor (BJT) where the majority charge carriers are electrons, consisting of two n-type semiconductor regions separated by a p-type region. It has three terminals: the emitter, base, and collector. Key characteristics and operation include:
- Forward Active Mode: The transistor operates in forward active mode when the base-emitter junction is forward-biased, and the base-collector junction is reverse-biased. In this mode, a small base current controls a much larger collector current.
- Current Flow: In an NPN transistor, current flows from the collector to the emitter when the base-emitter junction is forward-biased.
- Applications: NPN transistors are used in amplifiers, switches, and digital logic circuits.
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Operational Amplifier
An operational amplifier (op-amp) is a high-gain, direct-coupled amplifier with differential inputs and a single-ended output, used to perform a wide range of analog signal processing tasks. Op-amps are characterized by parameters such as input offset voltage, input bias current, bandwidth, and slew rate, which determine their performance in different applications.
Key features and applications include:
- High Gain: Op-amps have very high open-loop gain, which can be controlled using external feedback components.
- Differential Inputs: The op-amp amplifies the voltage difference between its two input terminals (inverting and non-inverting).
- Versatility: Op-amps can be configured for various functions, including amplification, filtering, integration, differentiation, and oscillation.
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Oscilloscope
An oscilloscope is an electronic test instrument used to visualize electrical signals in real-time. It displays the voltage of a signal as a function of time, allowing for analysis of signal characteristics like amplitude, frequency, and waveform shape.
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PAC, Pin Array Cartridge
A PAC is a component package that features a grid or array of pins extending from the bottom of the cartridge, allowing for easy insertion into sockets or through-holes on a PCBA.
Key features include:
- High Pin Density: The array of pins allows for a high number of connections in a compact area, making PACs suitable for complex and high-performance applications.
- Ease of Use: Designed for easy insertion and removal, PACs facilitate quick assembly and replacement of components.
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Package
A package refers to the protective casing that houses an integrated circuit (IC) or other electronic component, providing physical support, electrical connections, and protection from environmental factors.
Common types of packages include:
- DIP (Dual In-line Package): Features two parallel rows of pins for through-hole mounting.
- SOP (Small Outline Package): A surface-mount package with gull-wing leads extending from the sides.
- BGA (Ball Grid Array): Uses an array of solder balls on the underside of the package for surface mounting.
- QFP (Quad Flat Package): A surface-mount package with leads extending from all four sides.
The choice of package depends on the specific requirements of the application, including size, power dissipation, and mounting method.
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Pads
Pads are the flat, conductive areas on a PCB where electronic components are soldered to establish electrical connections.
Types of pads include:
- Surface-Mount Pads: Used for surface-mount technology (SMT) components, which are soldered directly onto the pads on the surface of the PCB.
- Through-Hole Pads: Used for through-hole components, where the component leads are inserted into holes and soldered to pads on the opposite side of the PCB.
- Thermal Pads: Larger pads designed to dissipate heat from power components, often connected to ground planes or heat sinks.
Pads must be properly designed and sized to ensure effective soldering and reliable connections. They are typically coated with a surface finish, such as HASL (Hot Air Solder Leveling), ENIG (Electroless Nickel Immersion Gold), or OSP (Organic Solderability Preservative), to enhance solderability and protect against oxidation.
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Part
A part refers to an individual electronic component or device that is used in the assembly of a circuit or system. Each part has a unique identifier, such as a part number or reference designator, used in schematics and BOMs (Bill of Materials) to specify and track components in a design. They can be categorized into various types, including:
- Passive Components: Such as resistors, capacitors, and inductors, which do not require an external power source to operate.
- Active Components: Such as transistors, diodes, and integrated circuits, which require an external power source and can amplify or switch electronic signals.
- Electromechanical Components: Such as switches, relays, and connectors, which involve both electrical and mechanical functions.
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Passive Components
Passive components are electronic components that do not amplify or generate electrical signals on their own. They can store, dissipate, filter, or control the flow of electrical energy. Key types of passive components include:
- Resistors: Limit the flow of electric current and divide voltages.
- Capacitors: Store and release electrical energy, filter signals, and block DC while allowing AC to pass.
- Inductors: Store energy in a magnetic field, filter signals, and manage impedance in AC circuits.
- Transformers: Transfer electrical energy between circuits through electromagnetic induction.
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PCB
A printed circuit board (PCB) is a flat, laminated board made of insulating material (commonly FR4) containing conductive tracks, pads, and vias that provide electrical connections for electronic components.
Key aspects of PCBs include:
- Layers: PCBs can be single-layer, double-layer, or multi-layer, with conductive traces on one or more layers separated by insulating material.
- Traces: Conductive pathways that connect different components and carry electrical signals.
- Pads: Flat areas on the PCB where components are soldered.
- Vias: Holes that allow electrical connections between different layers of a multi-layer PCB.
- Solder Mask: A protective layer applied over the conductive traces to prevent short circuits and corrosion.
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PCBA
A Printed Circuit Board Assembly (PCBA) is a PCB that has all the necessary electronic components mounted and soldered onto it, forming a functional electronic circuit or system. The process of creating a PCBA involves several steps:
- Component Placement: Electronic components are placed onto the PCB in their designated locations.
- Soldering: Components are soldered to the PCB using various techniques such as reflow soldering, wave soldering, or manual soldering.
- Inspection and Testing: The assembled PCBA is inspected and tested to ensure it meets quality standards and functions correctly.
PCBA is the final product that integrates all electronic components and connections, ready for use in electronic devices and systems.
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Photoconductive Cell
A photoconductive cell, also known as a light-dependent resistor (LDR), is a passive component whose resistance changes based on the intensity of light it receives. Photoconductive cells are used to detect light levels and control electrical circuits based on the amount of light. They are commonly used in light meters, automatic lighting controls, alarm systems, and other applications where light detection is required.
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Photodiode
A photodiode is a semiconductor device that converts light into an electrical current. It operates in reverse bias mode, where light photons generate electron-hole pairs that create a current. Photodiodes are highly sensitive to light, making them suitable for precise light detection and measurement. They also have fast response times, allowing them to detect rapid changes in light intensity.
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Photoresistor
A photoresistor, also known as a light-dependent resistor (LDR) or photoconductive cell, is a resistor whose resistance decreases as the intensity of light falling on it increases. Photoresistors are used to sense light levels and control circuits based on the detected light intensity.
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Piezoelectric Crystal
A piezoelectric crystal is a material that generates an electric charge in response to mechanical stress and can also deform when an electric field is applied.
Piezoelectric crystals have a unique atomic structure that lacks a center of symmetry. When mechanical pressure is applied to these crystals, it causes a displacement of positive and negative charge centers within the material. This displacement generates an electric voltage across the crystal. This is also called direct piezoelectric crystal, and it is used in sensors and energy harvesting devices. Conversely, when an electric field is applied, it causes mechanical deformation in the crystal. This is called the inverse piezoelectric effect, and it is used in actuators and precision movement devices.
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Pin
A pin refers to a connection point on a component or a connector. Pins are typically metallic and provide a physical and electrical connection point for soldering or other assembly techniques.
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Pin-out
A pin-out is a diagram or table that shows the functions and connections of each pin on an electronic component, connector, or integrated circuit. Pin-outs are essential for understanding how to correctly connect and use electronic components. They are typically included in datasheets, user manuals, and technical documentation to guide engineers and technicians.
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Plane
A plane refers to a large, continuous area of conductive material (typically copper) on a PCB layer. These planes serve various purposes:
- Power and Ground Distribution: Planes provide low-resistance paths for power and ground connections, ensuring stable voltage levels and minimizing voltage drops.
- EMI Reduction: Planes help reduce electromagnetic interference (EMI) by providing a large area for return currents and shielding signal traces.
- Thermal Management: Planes can dissipate heat generated by components, helping to manage the thermal performance of the PCB.
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Plasma
Plasma is an ionized gas consisting of free electrons and ions, which can conduct electricity and respond to magnetic fields. Plasma is used in various applications PCBA manufacturing, including:
- Plasma cleaning: This is a specialized cleaning technique that utilizes a low-temperature plasma to remove organic contaminants and improve surface adhesion for subsequent processes like soldering.
- Plasma etching: In advanced PCB fabrication processes, plasma etching might be used for precise removal of material during the creation of micro-features on the PCB surface.
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Plated Through Hole
A Plated Through Hole (PTH) is a hole in a PCB that is coated with a conductive material, typically copper, to allow electrical connection between different layers of the board. The process of creating PTHs involves drilling holes in the PCB and then plating the interior walls of the holes with a conductive material to form an electrical connection.
PTHs provide reliable interconnections between layers of a multilayer PCBA and they are also used for mounting through-hole components, such as resistors, capacitors, and integrated circuits, by inserting their leads through the holes and soldering them on the opposite side.
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PLC, Programmable Logic Controller
A PLC is an industrial digital computer designed to control manufacturing processes, machinery, or factory assembly lines.Key features and applications include:
- Programmability: PLCs can be programmed using various languages, such as ladder logic, structured text, and function block diagrams, to perform specific control tasks.
- Input/Output (I/O): PLCs have multiple input and output terminals for connecting sensors, actuators, and other devices.
- Rugged Design: Designed to withstand harsh industrial environments, including extreme temperatures, vibrations, and electrical noise.
- Real-Time Operation: PLCs operate in real-time, processing inputs and outputs to control processes accurately and efficiently.
PLCs are widely used in manufacturing, process control, automation systems, and other industrial applications where precise control and monitoring are required.
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Pogo Pin
A pogo pin, also known as a spring-loaded pin, is a type of electrical connector used in many electronic applications to establish a temporary or permanent connection between two devices. Pogo pins typically consist of three main parts:
- Plunger: The top part that makes contact with the mating surface. It is often rounded or pointed to ensure a good connection.
- Spring: Located inside the pin, the spring provides the necessary force to push the plunger outward, ensuring consistent pressure and contact.
- Barrel: The outer casing that houses the plunger and spring. It ensures the pin's structural integrity and provides a pathway for electrical current.
When a pogo pin is pressed against a contact pad or another connector, the plunger compresses into the barrel. The spring inside pushes back, maintaining a consistent force that keeps the connection stable and reliable. This design allows for repeated connections and disconnections without significant wear.
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PoP, Package on Package
Package on Package (PoP) is an advanced stacking technology used in microelectronic packaging. It involves vertically stacking two or more integrated circuit (IC) packages on top of each other and interconnecting them electrically using microbumps or other techniques.
Benefits of PoP
- Reduced size and footprint: PoP allows for a smaller overall package size compared to placing the ICs side-by-side on a PCB. This is beneficial for miniaturized electronic devices.
- Shorter interconnects: The vertical stacking reduces the electrical path length between the ICs, potentially improving signal integrity and performance.
- Increased functionality: PoP enables combining multiple ICs in a single stacked package, leading to more complex and feature-rich devices.
PoP designs face several challenges. Heat dissipation is a concern due to the increased density of components. Ensuring precise alignment and reflow soldering is necessary for reliable connections. PoP is also more expensive than traditional packaging methods because of the additional manufacturing steps and materials involved.
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Potentiometer
A potentiometer is an adjustable voltage divider with three terminals: two at the ends of a resistive element and one connected to a sliding wiper. The wiper moves along the resistive track, changing the resistance and adjusting the output voltage when connected to a voltage source.
Types of Potentiometers:
- Rotary Potentiometer: Has a knob or dial that you turn to move the wiper.
- Linear Potentiometer: Has a slider that moves in a straight line to adjust the wiper position.
Potentiometers are used in various applications to adjust voltage and resistance. They control volume in audio equipment, tune frequencies in radios, act as position sensors in joysticks, and adjust light brightness in dimmers.
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Press Fit Holes
Press fit holes are precisely sized holes in a PCB designed to accommodate press fit components, which are inserted and held in place by friction without the need for soldering. The holes are slightly smaller than the component pins, creating an interference fit that holds the pins securely in place. Press fit technology is especially useful in applications where components may need to be replaced or upgraded without the risk of damaging the PCB through repeated soldering and desoldering.
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Printed Wiring Board
A Printed Wiring Board (PWB) is an older term for what is now commonly known as a Printed Circuit Board (PCB). It refers to a board made of insulating material with conductive pathways printed or etched onto its surface to connect electronic components.
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PROM, Programmable Read Only Memory
PROM is a non-volatile memory that can be programmed once after manufacturing by the user to store permanent data. PROMs allow for custom data to be written after the chip is manufactured, providing flexibility in applications where the stored data does not need to be changed frequently. Key features and include:
- One-Time Programmability: Once programmed, the data in a PROM cannot be altered. This makes PROMs suitable for storing firmware, configuration settings, and other data that does not change.
- Programming: PROMs are programmed using a special device called a PROM programmer or burner, which applies a high voltage to specific cells to change their state.
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QFP, Quad Flat Package
QFP packages are a type of surface-mount technology (SMT) package, recognizable by their flat, outward-extending leads on all four sides. Here are the main features of QFP packages:
- Gull-wing Leads: QFP packages have gull-wing shaped leads that extend outward from all four sides of the package. These leads are soldered to the PCB pads.
- Visibility: The leads make visual inspection and rework easier compared to leadless packages.
- Variety: QFPs come in various sizes and lead counts, accommodating different design requirements.
- Thermal and Electrical Performance: While QFPs don't have the thermal pad found in QFNs, their performance is adequate for many applications. However, the longer leads can introduce higher inductance and resistance.
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Radial Lead
Radial leads are wire leads that extend out from the body of a component in a radial direction, perpendicular to the component's body. These are commonly found in through-hole components, such as capacitors and resistors. Radial leads are designed for insertion into holes on a PCB, where they are then soldered to establish electrical connections. This type of lead configuration provides mechanical stability and ease of mounting.
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Raspberry Pi
Raspberry Pi is a series of small, affordable single-board computers developed by the Raspberry Pi Foundation. Originally designed to promote computer science education, Raspberry Pi devices have gained popularity for various applications, from hobbyist projects to professional embedded systems. They feature a range of processing capabilities, input/output options, and connectivity features, making them versatile tools for learning and development.
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Receiver
A receiver is a device that receives and decodes signals transmitted from a sender or transmitter. Receivers are used in various applications, including radio, television, and communication systems. They convert incoming signals into a usable form, such as audio, video, or data, by amplifying, demodulating, and processing the received signals.
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Rectifier
A rectifier is an electronic device that converts alternating current (AC) to direct current (DC) by allowing current to flow only in one direction. Rectifiers are crucial components in power supplies and many other electronic systems.
Types of Rectifiers
- Diode Rectifiers: The most basic type, using one or more diodes to allow current to flow in only one direction.
- Half-Wave Rectifier: Uses a single diode to convert only one half of the AC waveform to DC, resulting in a pulsating DC output.
- Full-Wave Rectifier: Uses two diodes (with a center-tapped transformer) or four diodes (in a bridge configuration) to convert both halves of the AC waveform to DC, providing a smoother output.
- Bridge Rectifier: A common full-wave rectifier configuration that uses four diodes arranged in a bridge to provide full-wave rectification without the need for a center-tapped transformer.
- Smoothing and Filtering: Rectifiers are often followed by filter components, such as capacitors and inductors, to smooth out the pulsating DC and reduce ripple.
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Reference Designator
A reference designator is an alphanumeric code assigned to each component on a printed circuit board (PCB) or in a schematic diagram to uniquely identify it. It makes it easier to identify and locate them during assembly, testing, and troubleshooting.
Common prefixes are used to indicate the type of component, such as R for resistors, C for capacitors, U for integrated circuits, and Q for transistors. For example, R1, R2, C1, U1, Q1, etc.
Reference designators are used in bills of materials (BOMs), assembly drawings, and technical documentation to provide clear instructions for assembling and servicing the electronic device.
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Relay
A relay is an electromechanical switch that uses an electromagnet to open or close one or more sets of contacts enabling the control of a high-power circuit with a low-power signal. Relays are used in various applications to control electrical devices remotely or to switch high currents and voltages with a low-power control signal. They provide isolation between the control signal and the high-power circuit, enhancing safety and reliability.
Relays come in various contact configurations, such as SPST (Single Pole Single Throw), SPDT (Single Pole Double Throw), DPDT (Double Pole Double Throw), etc.
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Resist
A resist refers to a protective coating applied to a PCB to shield specific areas from chemical processes such as etching, plating, or soldering. Resists are essential for achieving high-quality and reliable PCBs, ensuring proper functionality and longevity of electronic circuits.
Types of Resist
- Photoresist: A light-sensitive material used in photolithography to transfer circuit patterns onto the PCB. It hardens when exposed to light, allowing the unexposed areas to be washed away, revealing the underlying copper for etching.
- Solder Resist (Solder Mask): A protective coating applied to the PCB to prevent solder from bridging between conductive areas during soldering, thereby avoiding short circuits. It also protects the PCB from oxidation and contamination.
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Resistors
A resistor is a passive electronic component that opposes the flow of electric current, providing a precise amount of resistance in a circuit. There are fixed resistors, variable resistors (such as potentiometers and rheostats), and special types like thermistors and varistors. Every resistor has the following parameters:
- Resistance Value: Measured in ohms (Ω), it determines how much the resistor opposes the current flow. The value is typically indicated by color codes or numerical markings.
- Power Rating: Specifies the maximum power the resistor can dissipate without damage, measured in watts (W)
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Rheostat
A rheostat is a variable resistor that is used to adjust the current flow in a circuit. A rheostat consists of a coil of resistive wire and a sliding contact that moves along the coil. The resistance can be varied by sliding a contact (wiper) along a resistive element, changing the length of the resistive path.
Rheostats are designed to handle higher currents and are commonly used for applications requiring adjustable resistance.
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Rotary Switch
A rotary switch is a switch that operates by rotating a knob or shaft to select one of multiple positions, each connecting different circuits. This versatile and reliable switch controls multiple circuits with a single interface. It is used in applications like selecting audio or video inputs, adjusting equipment settings, controlling multi-speed fans, and managing industrial machinery.
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Route
Route refers to the process of creating conductive pathways (also known as traces or tracks) on the printed circuit board to connect different electronic components according to the schematic diagram.
Routing can be done manually by the designer or automatically using software algorithms, adhering to design rules that dictate trace width, spacing, and via sizes. Effective routing ensures stable voltage levels, minimizes crosstalk and electromagnetic interference, and meets the electrical requirements of high-speed and high-frequency signals.
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Schmitt Trigger
A Schmitt Trigger is a type of comparator circuit that converts a noisy input signal into a clean digital output signal. It has two threshold levels: one for rising signals and one for falling signals. This feature is called hysteresis. Hysteresis helps the circuit ignore noise. When the input goes above the upper threshold, the output switches to high. When the input falls below the lower threshold, the output switches to low. The result is a stable digital signal.
Applications of Schmitt Triggers include signal conditioning, waveform shaping, and creating stable digital signals from analog inputs. They are commonly used in various electronics, such as in debouncing buttons and switches or in oscillators and timers.
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Schottky Diode
A Schottky diode is a special type of diode known for its low forward voltage drop and fast switching speed. It is made by joining a metal with a semiconductor, which reduces the voltage drop to about 0.2 to 0.3 volts. Schottky diodes can turn on and off very quickly, making them ideal for high-speed applications. They are commonly used in power supplies, radio frequency applications, and to protect circuits from voltage spikes. However, they have a higher reverse leakage current than regular diodes. Despite this, Schottky diodes are efficient and fast, making them useful in many electronic applications.
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SCR, Silicon Controlled Rectifier
A Silicon Controlled Rectifier (SCR) is a semiconductor device used to control high power. It has four layers and three terminals: anode, cathode, and gate. A small current to the gate turns the SCR on, allowing a large current to flow between the anode and cathode. The SCR stays on until the current drops below a certain level. SCRs are used in applications like light dimmers, motor speed controls, and power supplies. They can handle high voltages and currents but need the current to drop to turn off. SCRs are valuable for controlling high-power electrical systems.
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Semiconductor
Semiconductors are a class of crystalline solids with electrical conductivity properties falling between conductors (like metals) and insulators (like glass). Semiconductors can conduct electricity under certain conditions. Their ability to conduct can be altered by introducing impurities, a process called doping.
There are two types of doped semiconductors: N-type with extra electrons and P-type with extra holes.Silicon is the most commonly used semiconductor material. Other materials include germanium and gallium arsenide.Semiconductors are used in various electronic devices, such as transistors, diodes, and integrated circuits.
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Silicon Wafer
A silicon wafer is a thin, flat slice of silicon used to create electronic circuits and devices. Silicon is chosen for its excellent semiconductor properties. The process begins by growing a pure silicon crystal, which is then sliced into thin pieces. These wafers are polished to achieve smooth surfaces and are often doped with impurities to modify their electrical properties. Silicon wafers are crucial in the production of integrated circuits, solar cells, and other semiconductor devices. Available in various sizes, larger wafers enhance manufacturing efficiency.
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Silkscreen
Silkscreen, also known as legend or overlay, is a layer of ink applied to the surface of a printed circuit board (PCB) to provide information such as labels, identifiers, and graphical symbols for components, connectors, test points, and other features on the board.
The silkscreen layer is an important part of the PCB design process, serving both functional and informational purposes:
Component Labels: The silkscreen includes reference designators (e.g., R1, C2, U3) that correspond to the schematic diagram. These labels help identify where each component should be placed on the PCB, aiding in assembly and troubleshooting.
Polarity and Orientation Indicators: Silkscreen markings show the correct orientation for components like diodes, LEDs, and polarized capacitors to prevent damage.
Test Points: Test points are marked on the silkscreen to identify where measurements should be taken during testing and debugging. These markings make it easier for technicians to locate and probe the correct points on the PCB.
Connector and Pin Labels: Connectors and headers are labeled with pin numbers or signal names, making it easier to connect cables and other boards correctly.
Warnings and Instructions: The silkscreen includes vital information for safe PCB use and handling, such as caution symbols and voltage warnings.
Manufacturer Information: The silkscreen layer shows the PCB manufacturer, part numbers, and other details. This helps track production history and manage inventory.
Aesthetic and Branding Elements: Logos, trademarks, and other branding elements can be included in the silkscreen layer to identify the product and the company that produced it.
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SIP, System-in-Package
System-in-Package (SiP) is a packaging technology that integrates multiple integrated circuits (ICs) and passive components within a single package to form a complete functional system. SiP technology allows for the miniaturization of electronic systems by combining multiple components into one package. This approach enhances performance, provides design flexibility, and is commonly used in mobile devices, IoT, and automotive electronics.
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Short
A short (short circuit) is an unintended low-resistance connection between two points in an electric circuit, resulting in excessive current flow and potential damage. Shorts can occur due to various reasons, such as solder bridges, damaged insulation, conductive debris, or component failures. Detecting shorts involves using tools like multimeters, continuity testers, and thermal imaging cameras. Preventing shorts requires proper design practices, including maintaining adequate clearance between conductive traces, careful soldering, and thorough inspection.
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Slot Hole
A slot hole is an elongated aperture used for mounting components with non-cylindrical leads or for mechanical attachment. It ensures a secure fit for components with flat or rectangular leads, such as certain connectors, switches, and transformers. Slot holes also provide additional mechanical strength for components under stress or vibration, preventing them from becoming loose or detached.
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SMD (Surface-Mount Device) / SMT (Surface-Mount Technology)
An SMD is an electronic component designed to be mounted directly onto the surface of a printed circuit board (PCB). Unlike traditional through-hole components, SMDs do not have leads that pass through the PCB. Instead, they have small metal tabs or terminations that are soldered directly to the surface of the board. SMT is the method used to mount and solder SMDs onto the surface of a PCB.
Benefits of SMT and SMD
- Miniaturization: SMDs are smaller than through-hole components, allowing for more compact and densely packed PCBs.
- Automation: SMT processes are highly automated, leading to faster production times and reduced labor costs.
- Performance: SMT can improve the electrical performance of the circuit due to shorter lead lengths and reduced parasitic inductance and capacitance.
- Cost-Effectiveness: Reduced material usage and labor costs make SMT a more economical choice for mass production.
Read more: compare SMT assembly and through hole assembly.
Categories: Board Parts / Components
SOC, System on Chip
SoC is an integrated circuit that integrates all or most components of a computer or other electronic system onto a single chip. SoCs provide high performance, reduced size, and power efficiency, and are used in a wide range of modern electronic devices.
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SOIC, Small Outline Integrated Circuit
SOIC is a surface-mount IC package with gull-wing leads, offering a compact size and ease of manufacturing, making it suitable for various high-density electronic applications.
Features of SOIC:
- Gull-Wing Leads: The leads extend from the sides of the package and bend outward and downward, providing reliable connections to the PCB pads.
- Compact Size: Smaller than traditional through-hole packages, allowing for more compact and high-density PCB designs.
- Ease of Manufacturing: Supports automated assembly processes, improving production efficiency and reliability.
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Software
Software refers to the programs and operating information that tell a computer what to do and how to perform specific tasks. Software encompasses tools for design, simulation, manufacturing control, and testing, playing a vital role in developing and producing reliable PCBAs.
Common types of software:
- Design Software: Tools like CAD (Computer-Aided Design) software are used to create PCB layouts, schematics, and design files. Examples include Altium Designer, Eagle, and KiCad.
- Simulation Software: Used to simulate and analyze the behavior of electronic circuits before physical prototyping. This helps identify potential issues and optimize the design.
- Manufacturing Software: Software that controls automated manufacturing equipment, such as pick-and-place machines, reflow ovens, and inspection systems. Examples include Gerber file viewers and CAM (Computer-Aided Manufacturing) software.
- Testing and Debugging Software: Tools that assist in testing and debugging electronic circuits, ensuring they function as intended. Examples include JTAG debuggers and signal analyzers.
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Solder Balls
Solder mask is a protective layer applied to the surface of a PCB to prevent solder from bridging between conductive areas and to protect the board from environmental damage. Key functions include:
- Insulation: Provides electrical insulation between traces, pads, and other conductive areas, preventing shorts and bridging during soldering.
- Protection: Protects the PCB from moisture, contaminants, and mechanical damage, enhancing the durability and longevity of the board.
- Aesthetics: Gives the PCB a professional appearance, usually in colors like green, blue, black, or red.
- Alignment: Helps align components during assembly by defining solderable areas.
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Solder Mask
Solder paste is a mixture of fine solder powder and flux, used to temporarily attach surface-mount components to a PCB before reflow soldering. During reflow soldering, the solder paste melts, forming permanent electrical and mechanical connections between the components and the PCB. Solder paste must be stored and handled carefully to maintain its properties, typically requiring refrigeration and controlled humidity.
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Solder Paste
Solder paste material is a mixture of tiny solder balls and flux used to attach components to a PCB.. The solder paste is applied to the PCB using a stencil, covering the pads where components will be placed. When the board is heated in a reflow oven, the solder paste melts and forms electrical and mechanical connections between the component leads and the PCB pads.
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SOP, Small Outline Package
SOP is a compact surface-mount IC package. It is smaller than traditional dual in-line packages (DIP) and is designed to be mounted directly onto the surface of a PCB. SOPs have two parallel rows of pins, making them compact and suitable for applications where space is limited.
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Spacing
Spacing refers to the distance between various elements on the board, such as traces, pads, and components. Proper spacing is crucial to prevent electrical shorts, ensure signal integrity, and comply with manufacturing tolerances. Adequate spacing also helps with heat dissipation and reduces electromagnetic interference (EMI).
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SQFP
A Square Quad Flat Package (SQFP) is a type of surface-mount IC package with leads on all four sides. It is square-shaped and has a high pin count, making it suitable for complex circuits. SQFPs are used in applications requiring high-density interconnections, offering a balance between size and the number of pins.
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Subpanel
A subpanel is a method of grouping multiple smaller PCBs into a larger panel. This approach simplifies handling and processing during assembly. After assembly, the individual PCBs are separated from the subpanel. Subpanels help in optimizing the manufacturing process, reducing handling time, and increasing throughput.
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Substrate
A substrate is a base material of a PCB that provides mechanical support and holds conductive pathways. The most common substrate material is FR-4, a type of fiberglass-reinforced epoxy laminate. Substrates must have good electrical insulation properties, thermal stability, and mechanical strength to ensure the durability and performance of the PCB.
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Switches
Switches are electromechanical devices used to control the flow of electricity in a circuit. They come in various types, such as push-button, toggle, slide, and rotary switches. Switches are used to turn devices on and off, change modes, or control different functions within an electronic system. Proper placement and reliable connection of switches are important for the functionality of the final product.
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Sensors
Sensors are components that detect changes in the environment and convert them into electrical signals. Sensors are mounted onto the PCBA to measure various physical parameters like temperature, light, pressure, humidity, and motion. These signals are then processed by the electronic system to perform specific functions, such as triggering an alarm or adjusting a setting. Sensors play a crucial role in making devices smart and responsive to their surroundings.
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Tented Via
A tented via is a via (a small hole that connects different layers of a PCB) that is covered with solder mask. The solder mask covers the via completely, creating a "tent" over it. This helps prevent solder from flowing into the via during assembly, reduces the risk of shorts, and protects the via from contaminants and environmental factors. Tented vias are particularly useful in high-density PCBA designs where space is limited.
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Terminal
A terminal is a point of connection for electrical components on a PCBA. It serves as an endpoint for an electrical conductor and allows for the attachment of wires or other connectors. Terminals can be part of components like resistors, capacitors, or connectors, and they are critical for establishing reliable electrical connections in a circuit.
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Terminal Block
A terminal block is a modular, insulated block that secures two or more wires together. It allows for the convenient connection and disconnection of electrical circuits. Terminal blocks are commonly used in PCBAs to organize wiring and facilitate easy maintenance, testing, and modification of circuits. They come in various types, such as screw terminals, spring-clamp terminals, and barrier strips.
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Test Point
A test point is a designated location on a PCBA where electrical signals can be measured during testing and debugging. Test points are usually small pads or pins that provide easy access for probes or test equipment. They are strategically placed throughout the PCBA to allow for the verification of signal integrity, voltage levels, and functionality of different parts of the circuit. Test points are essential for ensuring the reliability and performance of electronic devices.
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Thermal Vias
Thermal vias are specialized vias in a PCB used to conduct heat away from heat-generating components to other parts of the board or to a heat sink. They are essentially small holes filled with conductive material, such as copper, that create a thermal path. By connecting different layers of the PCB, thermal vias help dissipate heat more effectively, improving the reliability and performance of the circuit.
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Thermistor
A thermistor is a type of resistor whose resistance changes significantly with temperature. Thermistors are used for temperature sensing and control applications. They can be found in devices like digital thermometers, battery chargers, and temperature compensation circuits. There are two main types:
- NTC (Negative Temperature Coefficient): Resistance decreases as temperature increases.
- PTC (Positive Temperature Coefficient): Resistance increases as temperature increases.
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Thermocouple
A thermocouple is a temperature sensor made from two different metals joined at one end. When the junction of the two metals is heated or cooled, it produces a voltage that can be measured and interpreted to determine temperature. Thermocouples are widely used in industrial applications due to their wide temperature range, durability, and fast response time. They are commonly used in ovens, kilns, engines, and other high-temperature environments.
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Thermostat
A thermostat is a device that automatically regulates temperature by switching heating or cooling systems on or off. It consists of a temperature sensor and a control unit. When the temperature deviates from the set point, the thermostat activates the heating or cooling system to restore the desired temperature. Thermostats are used in various applications, including home heating systems, refrigerators, and industrial climate control systems.
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Thin Film
Thin film refers to a very thin layer of material, often only a few nanometers to micrometers thick, deposited on a substrate. Thin films are used for creating resistors, capacitors, and other components. These films can be made from various materials, including metals, oxides, and nitrides. Thin film technology allows for precise control of component values and is used in applications requiring high performance and miniaturization.
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Through-Hole
Through-hole technology involves mounting electronic components by inserting their leads through holes drilled in the PCB and soldering them on the opposite side. This method provides strong mechanical bonds and is suitable for components that need to handle high power or mechanical stress. Through-hole components are larger than surface-mount devices (SMDs) and are often used in applications where durability and reliability are critical, such as in industrial and military equipment.
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TQFP, Thin Quad Flat Package
TQFP is a type of surface-mount IC package with leads on all four sides. It is characterized by its thin profile and low height, making it suitable for applications where space is limited. TQFP packages come in various pin counts, typically ranging from 32 to over 200 pins. They are commonly used in microcontrollers, memory chips, and other high-density integrated circuits.
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Toggle Switch
A toggle switch is a mechanical switch that uses a lever to open or close an electrical circuit. The lever can be moved to different positions to control the flow of electricity. Toggle switches are commonly used in a variety of applications, including household appliances, industrial machinery, and automotive controls. They are valued for their simplicity, durability, and ease of use.
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Trace
A trace is a conductive path on a PCB that connects different components. Traces are made from a thin layer of copper that is etched onto the surface of the board. They carry electrical signals and power between the components, essentially acting as the wiring of the circuit. The width and thickness of traces are designed based on the amount of current they need to carry and the requirements of the circuit.
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Track
A track is essentially the same as a trace. It refers to the copper pathways on the PCB that connect components and allow electrical signals to flow. Tracks must be carefully designed to ensure they can handle the required current and maintain signal integrity, avoiding issues like crosstalk and interference.
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Transducer
A transducer is a device that converts one form of energy into another. In electronics, transducers are used to convert physical quantities like temperature, pressure, light, or sound into electrical signals. Examples of transducers include microphones (which convert sound into electrical signals), thermocouples (which convert temperature into electrical signals), and accelerometers (which convert motion into electrical signals). Transducers are crucial in various applications, including sensors and measurement systems.
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Transformers
A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It consists of primary and secondary windings wrapped around a magnetic core. Transformers can step up (increase) or step down (decrease) voltage levels, making them essential in power distribution. They are used in power supplies, audio systems, and various other applications where voltage transformation is needed.
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Transistors
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It has three terminals: the emitter, the base, and the collector. By applying a small current or voltage to the base terminal, transistors can control a much larger current flowing between the collector and emitter. Transistors are fundamental building blocks in modern electronics, used in amplifiers, switches, and digital circuits. They come in various types, including bipolar junction transistors (BJTs) and field-effect transistors (FETs).
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Transmitter
A transmitter is an electronic device that sends out signals to communicate information over a distance. It converts electrical signals into radio waves, light waves, or other forms of electromagnetic energy, which are then transmitted through an antenna or optical fiber. Transmitters are used in various applications, including radio and television broadcasting, wireless communication, and remote control systems. They are essential in enabling communication over long distances without the need for physical connections.
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Trimmer
A trimmer, also known as a trimmer capacitor or trimmer resistor, is an adjustable component used to fine-tune circuits. It allows precise control of resistance or capacitance values to achieve the desired performance in electronic circuits. Trimmers are often used during the calibration and adjustment phase of circuit design to ensure optimal functionality. They are typically small, screw-adjustable components found in radio frequency (RF) circuits, oscillators, and filter networks.
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TTL, Transistor-Transistor Logic
TTL is a class of digital logic circuits built from bipolar junction transistors (BJTs) and resistors. TTL circuits are used to create digital devices and are known for their speed, reliability, and ease of use. They operate with a supply voltage of 5V and have defined voltage levels for logical "0" (typically 0V) and logical "1" (typically 5V). TTL technology has been widely used in digital computers, control systems, and other electronic devices. Although newer technologies like CMOS have largely replaced TTL in many applications, TTL remains important in understanding digital circuit design.
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Underfill
Underfill is a material used to provide mechanical support and improve the reliability of electronic component connections. It is applied between a chip and the substrate or between other components to fill gaps and prevent damage from thermal stress, vibration, and mechanical shock. Underfill is commonly used in flip-chip packaging and ball grid array (BGA) assemblies to enhance the durability and performance of the electronic device.
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USB, Universal Serial Bus
USB is a standard for connecting and transferring data between computers and peripheral devices. It supports plug-and-play installation and hot-swapping, allowing devices to be connected and disconnected without restarting the computer. USB ports and connectors come in various types, including USB-A, USB-B, USB-C, and micro-USB. USB is widely used for connecting devices such as keyboards, mice, printers, external storage, and smartphones, offering both power supply and data transfer capabilities.
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Variable Capacitor
A variable capacitor is a type of capacitor whose capacitance value can be adjusted. It consists of two sets of metal plates, with one set being movable relative to the other. By changing the overlap area between the plates, the capacitance can be varied. Variable capacitors are used in tuning circuits, such as in radio receivers, where precise adjustment of capacitance is required to select different frequencies. They allow for fine-tuning of the circuit's resonance frequency.
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Variable Resistor
A variable resistor, also known as a potentiometer or rheostat, is a resistor whose resistance can be manually adjusted. It consists of a resistive element and a sliding contact (wiper) that moves along the element to change the resistance. Variable resistors are used to control electrical parameters such as volume in audio equipment, brightness in lights, and sensitivity in sensors.
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Vee
Vee is often used to denote the negative power supply voltage in a circuit, especially in the case of bipolar junction transistors (BJTs) and operational amplifiers (op-amps). It is the opposite of "Vcc," which represents the positive supply voltage.
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Via
A via is a small hole in a PCB that allows electrical connections between different layers of the board. It is filled with a conductive material, usually copper, to create a pathway for electrical signals to travel from one layer to another. Vias are essential for multilayer PCBs, enabling complex routing of traces and interconnections. They come in various types, such as through-hole vias, blind vias, and buried vias, each serving specific design purposes.
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Via-in-Pad
Via-in-Pad (VIAP), in the context of Printed Circuit Board Assemblies (PCBAs), refers to a via (plated hole connecting layers) that is embedded within a solder pad. A Via-in-Pad offers several advantages for high-density PCB designs, including increased density, improved signal integrity, and enhanced reliability.
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Via Stub
A via stub is the portion of a via that does not connect to any trace or pad on the internal layers of a PCB. It is essentially an unused segment of the via that can create unwanted signal reflections and impedance discontinuities, particularly in high-speed or high-frequency designs. Via stubs can degrade signal integrity, so designers often use techniques like back-drilling to remove the stub and improve performance.
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VQFP, Very Thin Quad Flat Package
VQFP is a type of surface-mount integrated circuit package. It is similar to the standard Quad Flat Package (QFP) but has a thinner profile, making it suitable for applications where vertical space is limited. VQFP packages have leads on all four sides, allowing for high pin counts and making them ideal for complex ICs such as microcontrollers, microprocessors, and various other digital and analog components. Their thin profile helps reduce the overall size and weight of electronic devices.
Categories: Board Parts / Components
Voltage Divider
A voltage divider is an electrical circuit that produces an output voltage (V_out) that is a fraction of its input voltage (V_in). It typically consists of two resistors connected in series across a voltage supply. The output voltage is taken from the connection point between the two resistors. Voltage dividers are commonly used in electronic circuits to scale down voltages, set reference voltages, and create bias voltages.
Categories: Board Parts / Components
VSS/Vss/vss–
VSS (or Vss or vss–) stands for "Voltage Source Supply'' and is commonly used to denote the ground or zero voltage reference point in a circuit. It is the point against which all other voltages in the circuit are measured. In digital and analog circuits, VSS is typically connected to the negative terminal of the power supply. For example, in CMOS logic circuits, VSS is the ground pin, while VDD is the positive supply voltage pin. The consistent use of VSS as a ground reference helps maintain a standard notation in circuit diagrams and designs.
Categories: Board Parts / Components
Wafer–See Silicon Wafer
A wafer, also known as a silicon wafer, is a thin, flat slice of silicon that serves as the foundation for fabricating electronic circuits and devices. It is used in the production of semiconductors, including integrated circuits (ICs) and solar cells. The manufacturing process involves growing a pure silicon crystal, slicing it into thin wafers, and then polishing and doping them as needed.
Categories: Board Parts / Components
Wet Solder Mask
A wet solder mask is a liquid coating applied to a PCB to protect the board and its components during the soldering process. The solder mask prevents solder bridges from forming between closely spaced solder pads and traces by covering the areas where solder is not required. The wet solder mask is applied using a screen-printing process, similar to applying a stencil, and is then cured (hardened) by exposure to heat or ultraviolet (UV) light. This coating provides both electrical insulation and mechanical protection, ensuring the durability and reliability of the PCB.
Categories: Board Parts / Components
Wire
A wire is a single, flexible strand or rod of metal used to carry electrical current from one point to another. Wires are fundamental components in electrical and electronic systems, providing the means for connecting various components and circuits. They come in different materials, such as copper or aluminum, and various thicknesses, known as gauges. Wires can be insulated or bare, depending on the application.
Categories: Board Parts / Components
Zener Diode
A Zener diode is a diode designed to allow current to flow not only in the forward direction, like a regular diode, but also in the reverse direction when the voltage exceeds a specific value known as the Zener breakdown voltage. This characteristic makes Zener diodes useful for voltage regulation and protection in circuits. When connected in reverse bias, they maintain a stable output voltage despite changes in the input voltage or load conditions. Zener diodes are commonly used in power supplies, voltage reference circuits, and surge protectors.
Categories: Board Parts / Components