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Term	Full Name	Meaning
PCB	Printed Circuit Board	A board that supports and connects electronic components using?conductive pathways, tracks, or signal traces etched from copper sheets laminated onto a non-conductive substrate.

What is PCB?

In modern electronics, a Printed Circuit Board (PCB) is one of the essential components of the device. PCBs are the fundamental building blocks of modern technology, acting as the infrastructure that supports and interconnects electronic hardware components. Additionally, a printed circuit board (PCB) is a common component in everything from consumer electronics to?aerospace and medical devices.

Moreover, PCBs were designed to supersede the conventional wire-to-wire connections made through harnesses — providing a method to?assemble electronic circuits that could be far more compact, reliable, and efficient. They are created by etching or printing conductive routes on an insulating substrate, like fiberglass or plastic, enabling the flow of electricity between components.

About PCBasic

Time is money in your projects – and PCBasic gets it. PCBasic is a PCB assembly company that delivers fast, flawless results every time. Our comprehensive PCB assembly services include expert engineering support at every step, ensuring top quality in every board. As a leading PCB assembly manufacturer, we provide a one-stop solution that streamlines your supply chain. Partner with our advanced PCB prototype factory for quick turnarounds and superior results you can trust.

PCB Components

A PCB has the following main elements:

·&苍产蝉辫;Base Material: Most commonly fiberglass or plastic, that provides structural support.

·&苍产蝉辫;Copper Layers: A copper foil portion is laminated onto the substrate in thin layers to form the?conductive pathways.

·&苍产蝉辫;Solder Mask: A robust layer that is coated over the copper to preclude short circuits and oxidation.

·&苍产蝉辫;Silkscreen: A layer used to print labels, logos, or component identifiers on the PCB.

·&苍产蝉辫;Electronic Component: Integrated circuits (ICs), resistors, semiconductors, etc. are on the board.

PCB Layers

PCBs comprise various layers that support functionality, durability, and performance. PCB Layers Overview PCB layers can be categorized as follows:

 

Base Material (Substrate Layer)

FR4 (fiberglass-reinforced epoxy) generally constitutes the PCB's base. It gives mechanical strength and insulation.

Applications: 

·&苍产蝉辫;Used in all PCBs as a foundation layer.

Advantages: 

·&苍产蝉辫;Long lasting.

·&苍产蝉辫;Electrical insulating.

·&苍产蝉辫;Heat resistant.

Disadvantages:

·&苍产蝉辫;Varies in cost.

·&苍产蝉辫;Thermal performance.

Copper Foils (Conductive Traces)

It’s thin sheets of copper pressed onto a substrate. The traces are etched to allow the electrical current to flow. Commonly seen in single-layer, double layer and multi-layer PCBs.

Application: 

·&苍产蝉辫;Used in all types of PCBs for passing on the electric signals between components.

Advantages:

·&苍产蝉辫;Great conductivity.

·&苍产蝉辫;Good for high data rate signals.

·&苍产蝉辫;Power capable.

Disadvantages: 

·&苍产蝉辫;Increases cost.

·&苍产蝉辫;Increases complexity of manufacturing.

Signal Layers

Layers whose purpose is to transfer electrical signals between components. A multi-layer PCB comprises many signal layers stacked one above the other for complexity in the circuit.

Applications:

·&苍产蝉辫;Used in multi-layer PCBs to route signals in high-density designs (i.e., processors, GPUs).

Advantages: 

·&苍产蝉辫;Minimizes the interferences on the signal.

·&苍产蝉辫;Permits a complex route.

·&苍产蝉辫;Improves the functionality of PCB.

Disadvantages:

·&苍产蝉辫;Increased PCB complexity.

·&苍产蝉辫;Designed very carefully to avoid crosstalk.

Power Plane & Ground Plane

Power Plane: A layer of thick copper that distributes power (VCC) across the PCB.

Ground Plane: A copper layer that gives a return path to the current (the ground).

Applications: 

·&苍产蝉辫;Used in multilayer printed circuit boards for high-speed electronics for stable power distribution.

Advantages: 

·&苍产蝉辫;Minimized electrical noise.

·&苍产蝉辫;Increased signal integrity.

·&苍产蝉辫;Ensures reliable power delivery.

Disadvantages: 

·&苍产蝉辫;Increases complexity and manufacturing cost.

Insulating Material (Dielectric?Layer)

Insulating material keeps conductive layers apart to avoid shorting. It is composed of materials such as prepreg (pre-impregnated fiberglass).

Applications: 

·&苍产蝉辫;Used in all PCBs to insulate the conductive layers and to avoid short circuits.

Advantages: 

·&苍产蝉辫;Insulates and minimizes interference.

·&苍产蝉辫;Enhances thermal stability.

Disadvantages:

·&苍产蝉辫;Not all materials have the same dielectric constant which affects signal performance

 

Solder Mask Layers

It is a protective coating covering the copper traces. It is usually green, blue or red. This layer helps avoid oxidation and unwanted solder bridges.

Applications:

·&苍产蝉辫;Used in all PCBs to cover copper traces and avoid solder bridging.

Advantages:

·&苍产蝉辫;Protects from oxidation.

·&苍产蝉辫;Increases durability.

·&苍产蝉辫;Provides better contact for soldering.

Disadvantages: 

·&苍产蝉辫;Requires precision in application.

·&苍产蝉辫;Improper masking can create defects in manufacturing.

Silkscreen Layer

It is text on paper or symbols (namely component labels, logos, reference indicators). Silkscreen layer helps assists with assembly and debugging.

Applications: 

·&苍产蝉辫;Used in all PCBs for component, logo, and reference indicator labels.

Advantages: 

·&苍产蝉辫;Helps with assembly, debugging, and documentation.

Disadvantages:

·&苍产蝉辫;Limited in marking size.

·&苍产蝉辫;Requires a professional approach for high-density PCBs.

Solder Paste Layers (For SMT Assembly)

It is used during Surface Mount Technology (SMT) assembly. Solder paste is included for attaching components.

Applications:

·&苍产蝉辫;Used in Surface Mount Technology (SMT) PCBs for placing components.

Advantages:

·&苍产蝉辫;Secure electrical connections.

·&苍产蝉辫;Increases precision during automated assembly.

Disadvantages: 

·&苍产蝉辫;Stencil printing is needed, and improper paste application can lead to defects.

Keep-Out Layer

The keep-Out layer designates forbidden zones where components or traces should not be placed. It ensures adequate spacing and prevents manufacturing quality issues.

Applications:

·&苍产蝉辫;Limits what to place in which area in PCB design components or traces.

Advantages: 

·&苍产蝉辫;Helps keep the layout from becoming congested, the manufacturability and spacing are correct.

Disadvantages:

·&苍产蝉辫;Restricts design flexibility (demands careful planning).

Types of PCB Based on Layers

Single-Layer PCB:

A Single-Layer PCB has a single conductive layer (most?commonly copper) on a non-conductive substrate (most often FR4, phenolic, or paper-reinforced epoxy). Copper traces are used to create the electrical connections on the board, which?are then coated with a solder mask to protect against oxidation. Simple?electronic devices mainly use this type of PCB to manufacture low-cost.

It has only one layer. That layer can be of:

·&苍产蝉辫;Substrate Layer (Base Material): The composition is normally FR4, phenolic?resin, or epoxy

·&苍产蝉辫;Conductive Layer: A thin layer of copper for circuit pathways.

·&苍产蝉辫;Solder Mask: Prevents traces from short-circuiting and corrosion.

·&苍产蝉辫;Silkscreen: To identify what components are on the board.

Applications:

·&苍产蝉辫;Calculators.

·&苍产蝉辫;Power supplies.

Double-Layer PCB

A?Double-Layer PCB contains copper conductive material on both PCB sides. Vias (plated through-holes) provide electrical interconnections between layers, allowing?for more compact circuits. This type of?PCB is a bit more versatile than single-layer types and accommodates moderately complex circuitry.

Applications:

·&苍产蝉辫;Industrial Controls

·&苍产蝉辫;Automotive Electronics

·&苍产蝉辫;Smartphones & Audio Devices

It has two layers. Those layers can be:

·&苍产蝉辫;Substrate Layer: FR4 or epoxy resin.

·&苍产蝉辫;Bottom Copper Layer: The conductive paths?for circuits.

·&苍产蝉辫;Top Copper Layer: Additional circuitry for higher complexity.

·&苍产蝉辫;Vias: Were used to make electrical connections between the top and bottom layers.

Multi-Layer PCB

A Multi-Layer PCB is a layer of three or even more punched out conductive layers placed on top of each other with dielectric layers of insulation between each of them. For example, high speed, compact structure is used in the military, computers, communication and other equipment.

Applications:

·&苍产蝉辫;Smartphones & Computers

·&苍产蝉辫;Medical Equipment

·&苍产蝉辫;Defence Space & Security

·&苍产蝉辫;Telecommunications at High Speed

Multi-Layer has 4+ layers. Those layers can be:

·&苍产蝉辫;Cores Substrate: Structural strength

·&苍产蝉辫;Copper Layers: To achieve circuit complexity,?several conductive layers

·&苍产蝉辫;Isolation layer: Sits between conductive?layers.

·&苍产蝉辫;Power & Ground Planes: Minimize?signal interference and carry power.

·&苍产蝉辫;Solder Mask?& Silkscreen Layers: Protection and identification.

Flexible PCB:

Flexible PCBs are comprised of flexible materials (commonly polyimide (PI)?or polyester (PET)) which can bend, twist, or fold without breaking. These?are extensively used in wearable devices, automotive electronics, and Aerospace applications.

Applications:

·&苍产蝉辫;Smartphone & Wearable Devices.

·&苍产蝉辫;Automotive Dashboards.

·&苍产蝉辫;Medical Devices.

·&苍产蝉辫;Spacecraft & Satellites.

Flexible PCB’s layers vary board to board. Those Layers can be:

·&苍产蝉辫;Flexible Substrate (Polyimide or PET).

·&苍产蝉辫;Copper Conductive Layer.

·&苍产蝉辫;Adhesive Layer.

·&苍产蝉辫;Coverlay, protective.

·&苍产蝉辫;Silk Screened for components.

Rigid PCB

A Rigid-Flex PCB is a type of PCB that combines delta rigid and?flexible sections in a single board. It is used in small devices with restricted volume such as?military devices, cameras, and medical implants.

Applications:

·&苍产蝉辫;Healthcare MID?(Medical Devices (pacemakers, hearing aids).

·&苍产蝉辫;Cameras & Wearable Tech.

·&苍产蝉辫;Industrial Control Systems.

Layers in Rigid-Flex PCB:

·&苍产蝉辫;Rigid Sections (FR4 Material)

·&苍产蝉辫;Innovations For Flexible Sections (Polyimide Substrate)

·&苍产蝉辫;Copper Conductive Layers

·&苍产蝉辫;Prepreg & Adhesive Layers

·&苍产蝉辫;Flex Sections: Protective Coating

High-Frequency PCB:

A High-Frequency PCB is capable of working at frequencies above 1 GHz with the help of low-loss materials, such as PTFE (Teflon) and Rogers laminates. This is very important aspect of RF (Radio Frequency) and microwave applications.

Applications:

·&苍产蝉辫;5G Base Stations.

·&苍产蝉辫;Radar & GPS Systems.

·&苍产蝉辫;Satellite Communication.

·&苍产蝉辫;High-Speed Data Processing.

Layers in High-Frequency PCB:

·&苍产蝉辫;PTFE or Rogers Substrate.

·&苍产蝉辫;Copper Conductive Layers.

·&苍产蝉辫;Dielectric Insulating Layers.

·&苍产蝉辫;Power & Ground Planes.

·&苍产蝉辫;Solder Mask & Silkscreen.

HDI PCB

HDI PCB (+High-Density Interconnect PCB) is a type of printed circuit board that has a high density of pads, traces, and?vias. It employs microvias, blind and buried?vias, and fine trace widths to enable miniaturization and high-speed signal transmission. These HDI PCBs are vital?for small form-factor electronic devices such as smartphones, laptops, and state-of-the-art medical instrumentation.

Applications:

·&苍产蝉辫;Smartphones & Tablets

·&苍产蝉辫;Laptops & Wearable Tech

·&苍产蝉辫;Medical Devices

·&苍产蝉辫;Automotive Electronics, ADAS (Advanced Driver Assistance?Systems).

·&苍产蝉辫;Aerospace?& Military: Applications in satellites, avionics, and defense systems.

·&苍产蝉辫;High-Speed Computing

·&苍产蝉辫;IoT Devices & Equipment for 5G Enterprise

Some include HDI PCBs that can have different layers depending on the design requirement. The typical layers include:

·&苍产蝉辫;Core Substrate: Main layer material, usually?FR4, PTFE, or Rogers laminate.

·&苍产蝉辫;Copper Layers: Several conductive layers are used?for power, ground and signal routing

·&苍产蝉辫;Microvias (Laser Drilled Vias): Vias interconnect differing layers effectively.

·&苍产蝉辫;Dielectric Layers: Insulating layers interposed between conductive Signal traces.

·&苍产蝉辫;Prepreg Layers: Put adhesive material between layers to bond them.

·&苍产蝉辫;Power?& Ground Planes: Provide stable power and reduce noise.

·&苍产蝉辫;Solder Mask & Silkscreen: as the need to protect & label the components.

Structure of?HDI PCB Types:

·&苍产蝉辫;1+N+1?(Single HDI Layer): one HDI layer on both sides

·&苍产蝉辫;2+N+2 (Double HDI Layer): Two HDI layers on all sides.

·&苍产蝉辫;Any-Layer HDI: Microvias connect any layer for ultimate design flexibility.

PCB vs. PCBA

Features	PCB	PCBA
Definition	A bare board without components.	An assembled PCB with soldered devices.
Functionality	Non-functional.	Operational electronic circuit.
Manufacturing	Etching, drilling, lamination.	Placement of components, soldering (SMT/THT).
Testing	Checks for continuity/shorts.	Functional and performance testing.

 

Key Differences

·&苍产蝉辫;PCB is just a board, while PCBA is an operation-ready electronic module.

·&苍产蝉辫;PCBs are passive structures, while PCBAs incorporate active components such as microcontrollers, resistors, capacitors, and ICs.

·&苍产蝉辫;PCB is the main component of the PCBA process while PCBA emphasizes the assembly and function of circuits, while PCB is the fabrication of the board itself.

·&苍产蝉辫;Testing the PCBA is more expensive, because it verifies the operational performance of the circuit board, while PCB testing only checks for continuity and board structure defects.

PCBasic's PCBA Services

We provide PCB assembly (PCBA) one-stop service, including:

Prototyping & Low-Volume Production.

海角社区 & Manufacture at High Speeds.

Automated SMT and Through-Hole Assembly.

Rigid & Flex & Rigid-Flex PCBs.

Quality Assurance (AOI, X-Ray, Functional Testing, Flying Probe Testing...).

Conclusion

PCB and PCB layers along the types of PCB are crucial for electronics design. The stacks of boards in?multi-layer PCBs can be daunting, but each layer (copper, substrate, solder mask, silkscreen, etc.) has its own part to play in the functionality of the device.

Through quality design, selection of proper materials, and adherence to testing standards, engineers can enhance the reliability and lifetime of the PCB.For engineers,?knowing a PCB's materials, layer structures and design best practices is vital to ensure that their electronics will be longlasting and high-performing. Even hobbyists and students can make their projects come alive, using inexpensive PCB?design software.

With new technologies, such as IoT, AI hardware, and wearable technology, demand for PCBs will?never fade. Whether you are repairing a defective board or deploying a new revolutionary device, familiarity with PCB fundamentals can help you succeed?in the consistently-escalating electronic domain.