A printed circuit board (PCB) assembly could be just the thing you need for your business. But in order to really understand the purpose of a printed computer circuit board and how a computer circuit board works, you have to understand the basic technology behind the product.

In this guide, we’ll break down the fundamentals of computer circuit boards, explore the types and components involved, and explain why investing in a quality PCB assembly can give your business a competitive edge.

Understanding the Basics: What Is a Computer Circuit Board?

Electric circuits are made up of wires and other components, such as light bulbs, transistors, computer chips, and motors. Conductive materials make up the wires that connect the components of the circuits.

Copper and aluminum are most frequently used as conductors, but gold is sometimes used for its superior resistance to corrosion.

The Building Blocks of an Electric Circuit

To understand how a computer circuit board works, it’s helpful to understand the core principles of electric circuits. At their simplest, electric circuits are composed of:

• Conductive materials like copper or aluminum
• Power sources such as batteries or external current
• Loads (components like LEDs, motors, or microchips)
• Control elements like switches and resistors

The key to any functioning electronic device is the ability to create a closed loop that allows current to flow and perform work.

Different Types of Circuits

In the world of electronics and electrical engineering, understanding the various types of circuits is essential to designing and troubleshooting any system, especially when working with a computer circuit board. Circuits serve as the foundation for transmitting power or data and dictate how electrical energy flows through a system.

Broadly speaking, circuits fall into two categories: power circuits and electronic circuits. Each type serves a distinct purpose and plays a vital role in our homes, businesses, and the technology we use daily.

Power Circuits

Power circuits transfer and control large amounts of electricity. Examples of power circuits are power lines and residential or business wiring systems.

The major components of power circuits are generators at one end and lighting systems, heating systems, or household appliances at the other end. Power lines, transformers, and circuit breakers are in between the two.

Electronic Circuits

Electronic circuits, on the other hand, are responsible for processing and transmitting information. These circuits operate at much lower voltages and are the backbone of all digital and analog devices such as computers, radios, TVs, radars, and cell phones.

Common Configurations of Circuits

Understanding how circuits are configured is crucial for both power and electronic applications. The design and layout affect current flow, voltage distribution, and overall functionality.

Closed Circuit

If you’re working with a closed circuit, you’re working with a complete path for current to flow from the power source, through the load, and back.

Open Circuit

An open circuit means the path is broken or incomplete, preventing current from flowing. It typically indicates a switch is open, a wire is disconnected, or a component has failed.

Short Circuit

A short circuit is a path of low resistance and can occur when two bare wires in a circuit touch each other. This can be hazardous, leading to overheating, component damage, or fire, which is why circuit protection is critical in both power and computer circuit board designs.

Series Circuits vs. Parallel Circuits

Both series and parallel circuits are used in power and electronic applications, but each behaves differently in terms of current flow and voltage distribution.

For example, resistors may be arranged in series to divide voltage, while capacitors might be placed in parallel to increase total storage capacity.

Series Circuit

In a series circuit, the same current flows through every component—think of a string of Christmas lights! If one goes out, they all go out; no current will flow, and none of the lights will go on.

Parallel Circuits

When you think of a parallel circuit, think of blood vessels that branch off from an artery and connect to a vein. It’s the same idea with wires; one acting as the “artery” and one acting as the “vein” with smaller wires attached. The smallest wires have the same voltage applied, but different amounts of current flowing through them, depending on the individual wiring.

Circuit Classifications

One way that circuits are classified is regarding the current flow.

Direct Current

Some of the earliest ones to ever exist were powered by a battery, allowing for a current to flow steadily in one direction. This is known as direct current (DC). Electronic circuits generally run on DC, with AC converted internally.

Alternating Current

To accommodate the need for power to travel over long distances, the alternating current, or AC, was invented by engineer Nikola Tesla. AC currents are always changing and reverse directions continuously.

With this type of current, it is possible to use transformers to change the level of voltage, which is necessary for electronic circuits.

What Does This Have To Do With Printed Computer Circuit Boards?

The purpose of a printed circuit board is to hold an electronic circuit together. When all the different components are attached to it, it is called a printed computer circuit board assembly, or PCBA.

A multilayer PCB typically contains about ten stacked layers, enabling complex 3D circuitry. That being said, the number of layers can exceed 30! Talk about complex PCBs.

Common Components of a Circuit Board

Components soldered onto the PCB are essential for conducting electricity on the boards. Here are some of the components included on a computer circuit board.

One of the best ways to understand the products we create is to study the basic components. The world of circuits and circuit boards is vast, and there is always something new to learn.

This knowledge is valuable whether you’re exploring a new advancement or managing an existing PCB project.

1. Transistors: The Building Blocks of Logic

Transistors are arguably the most crucial active components on a computer circuit board. They function as tiny electronic switches or amplifiers that can turn current on or off and control the flow of electrical signals. A single microprocessor may contain billions of transistors packed into an integrated circuit.

Key Functions:

• Switching digital signals on and off
• Amplifying electrical signals
• Enabling logical operations in CPUs and microcontrollers

Applications:

• Core processors
• Memory chips
• Voltage regulators
• Signal modulators

Without transistors, digital computing would not be possible. They form the foundation of all modern electronics, including computers, smartphones, and embedded systems.

2. Resistors: Controlling Current Flow

Resistors are passive components that introduce a specific amount of resistance into the circuit. Their primary role is to limit the flow of electrical current, divide voltages, and protect sensitive components from excessive power.

Key Functions:

• Regulate the current to safe levels
• Provide a voltage division
• Set bias points for transistors
• Reduce signal noise

Common Types:

• Fixed resistors
• Variable resistors (potentiometers)
• Surface-mount resistors (for compact designs)

On a computer circuit board, resistors are strategically placed to ensure consistent and safe power distribution, especially in logic circuits and analog signal pathways.

3. Capacitors: Storing and Releasing Energy

Capacitors are components that temporarily store electrical energy and release it when needed. They are widely used in computer circuit board designs to stabilize power supplies, filter signals, and maintain stable voltage levels.

Key Functions:

• Store and discharge electrical energy
• Filter high-frequency noise
• Stabilize voltage and power flow
• Enable timing circuits

Types Used in PCBs:

• Ceramic capacitors (small, stable)
• Electrolytic capacitors (higher capacity)
• Tantalum capacitors (compact with good frequency response)

Capacitors are essential in both digital and analog sections of a PCB, improving overall performance and preventing signal degradation.

4. Inductors: Managing Magnetic Energy

Inductors are passive components that store energy in a magnetic field when current flows through them. They are less common in purely digital logic sections, but essential in power and RF circuits.

Key Functions:

• Block high-frequency AC signals
• Store energy in DC-to-DC converters
• Reduce electromagnetic interference (EMI)

Applications:

• Power supply filtering
• Radio-frequency (RF) applications
• Noise suppression in switching circuits

In large or high-frequency computer circuit boards, inductors ensure cleaner signal transmission and stable power delivery, particularly in advanced computing and telecommunications equipment.

5. Diodes: Directing Current Flow

Diodes are semiconductor devices that allow current to flow in one direction only. They act as gatekeepers, protecting other components on the computer circuit board from voltage spikes or reverse polarity.

Key Functions:

• Prevent reverse current flow
• Protect circuits from voltage surges
• Convert AC to DC in rectifiers
• Emit light in LEDs

Common Types:

• Zener diodes (for voltage regulation)
• Light-emitting diodes (LEDs)
• Schottky diodes (for high-speed switching)

Whether serving as simple protection devices or enabling signal control, diodes play a vital safety and efficiency role in PCB architecture.

CAD

The most advanced designers of computer circuit boards use computer-aided design programs, or CAD. These tools provide the most accurate way to design circuit boards because of the complexity of digital computers, as they use millions of transistors.

Types of PCBs

There are several different types of PCBs you can choose from, depending on your planned usage. A computer circuit board specialist can help you determine which type is right for you, depending on the application of your PCB.

1. Single-Sided PCBs

Single-sided PCBs are the simplest and most cost-effective type of computer circuit board. They consist of one layer of conductive material, typically copper, on one side of an insulating substrate.

Key Features:

• Components and traces are mounted on a single side
• Ideal for straightforward, low-density circuit designs
• Easy to manufacture and mass-produce

Applications:

• Calculators
• LED lighting systems
• Power supplies
• Consumer electronics

Best for low-cost applications that don’t require advanced functionality or high-speed signal transmission.

2. Double-Sided PCBs

As the name suggests, double-sided PCBs have conductive copper layers on both the top and bottom sides of the board. This allows for more complex circuitry and higher component density than single-sided boards.

Key Features:

• Vias (plated holes) connect circuits on both sides
• Increased design flexibility and functionality
• Supports surface-mount and through-hole components

Applications:

• HVAC systems
• Automotive dashboards
• Industrial control systems
• Amplifiers

Best for mid-range applications that require more complex routing and increased component space.

3. Multi-Layer PCBs

Multi-layer PCBs consist of three or more conductive layers stacked together, separated by insulating materials. These boards are essential for advanced electronics where high-speed signals and compact design are critical.

Key Features:

• Offers greater circuit density and reduced board size
• Minimizes electromagnetic interference (EMI)
• Supports high-performance, high-speed processing

Applications:

• Smartphones and tablets
• Data storage devices
• Servers and networking equipment
• Medical imaging systems

Best for high-tech applications that require compact designs, high-speed signal integrity, and complex functionality.

4. Rigid PCBs

Rigid PCBs are made from solid, inflexible substrates (often fiberglass-reinforced epoxy) that retain their shape over time. They are the most common form of computer circuit board used in industrial and commercial applications.

Key Features:

• Extremely durable and structurally stable
• Excellent thermal resistance and mechanical strength
• Long lifecycle

Applications:

• Military-grade hardware
• Aerospace controls
• Consumer electronics
• Robotics

Best for applications that demand durability and structural integrity, especially in high-vibration or high-stress environments.

5. Flex PCBs (Flexible Circuits)

Flexible PCBs are made from materials like polyimide that allow the board to bend and twist without damaging the circuits. They’re ideal for small or oddly-shaped devices where rigid boards are not practical.

Key Features:

• Lightweight and space-saving
• Can flex during use or installation
• Reduces assembly time and complexity

Applications:

• Wearable technology
• Foldable smartphones
• Camera modules
• Medical devices

Best for compact, lightweight products with dynamic movement or tight enclosures.

6. Rigid-Flex PCBs

Rigid-flex PCBs combine the benefits of both rigid and flexible boards into a single, hybrid solution. They contain both flexible layers and rigid sections, allowing complex 3D designs and improved durability.

Key Features:

• Enhanced reliability with fewer connectors and interconnects
• Reduces weight and space
• Increases design versatility

Applications:

• Military avionics
• Medical implants and diagnostic equipment
• Consumer electronics
• Aerospace and satellite systems

Best for devices requiring high reliability, rugged performance, and space-efficient design.

7. High-Frequency PCBs

High-frequency PCBs are specially designed to carry signals at high speeds with minimal loss or interference. They use specialized materials like PTFE (Teflon) to maintain signal integrity.

Key Features:

• Designed for frequencies in the hundreds of MHz or higher
• Low dielectric constant and minimal signal loss
• Precise impedance control

Applications:

• Microwave systems
• Satellite communications
• GPS technology
• RF amplifiers and antennas

Best for high-speed, high-frequency communication systems where performance and accuracy are critical.

8. Aluminum-Backed PCBs

Aluminum PCBs use a metal-backed substrate for improved thermal management and electromagnetic shielding. This type of computer circuit board is ideal for high-power applications where heat dissipation is a concern.

Key Features:

• Excellent heat dissipation and mechanical stability
• Reduces hot spots and extends component life
• Improved durability under high-stress conditions

Applications:

• LED lighting systems
• Power converters
• Automotive electronics
• Solar panel controllers

Best for high-power applications or environments with excessive heat or electromagnetic interference.

Manufacturing Process of A Computer Circuit Board

The manufacturing of a computer circuit board is a detailed and highly precise process that ensures the board can support complex computing functions.

These boards, often multi-layered, serve as the backbone of computers, housing and interconnecting critical components like CPUs, memory, and graphics chips. Here’s a step-by-step overview of how they’re made.

1. PCB Design and Engineering

Everything starts with a digital blueprint. Engineers use CAD (Computer-Aided Design) software to design the layout of the computer circuit board, mapping component placement and signal routing across multiple layers.

2. Layer Stack-Up and Lamination

Computer circuit boards are usually multi-layered, with several layers of copper and insulating material.

Layers are stacked in a specific order, aligned precisely, and bonded together using heat and pressure. This forms the basic board structure.

3. Imaging and Etching

Each layer is coated with a light-sensitive film and exposed to UV light through a mask of the circuit pattern. The exposed areas harden, and the unexposed areas are removed.

Then, chemical etching removes unwanted copper, leaving behind the precise copper traces that form the circuit pathways.

4. Drilling

Tiny holes, called vias, are drilled through the board to connect the different layers or allow for component leads.

High-speed, computer-controlled drilling machines are used to ensure micrometer-level accuracy, especially important in high-performance computing boards.

5. Copper Plating

Once holes are drilled, they are plated with copper to make them electrically conductive. This is critical for allowing signals to pass between layers in a multi-layer computer board.

6. Solder Mask Application

A solder mask is applied to insulate the copper traces and prevent solder from bridging during assembly.

This is typically green, but other colors may be used in custom boards. Openings are left only where soldering is required.

7. Silkscreen Layer

Component labels, part numbers, logos, and other identifiers are printed on the board in white or contrasting ink. This silkscreen layer helps guide the assembly and repair processes.

8. Surface Finish

The exposed copper pads receive a surface finish to improve solderability and prevent oxidation.

Common finishes for computer PCBs include:

• ENIG (Electroless Nickel Immersion Gold) – offers excellent conductivity and durability.
• HASL (Hot Air Solder Leveling) – a cost-effective option.
• OSP (Organic Solderability Preservative) – eco-friendly and used in high-volume boards.

9. Component Mounting

Now the board is ready for components. Using automated machines, thousands of tiny components, like processors, transistors, memory modules, resistors, and capacitors, are precisely placed on the board.

There are two primary mounting technologies used in PCB assembly.

Surface-Mount Technology (SMT)

With SMT, components are mounted directly onto the surface of the board without the need for drilled holes. This technique supports compact, high-density designs and is perfect for modern electronics like smartphones, computers, and wearables.

SMT allows for faster assembly and greater automation, reducing production time and costs.

Through-Hole Technology (THT)

In THT, component leads are inserted into pre-drilled holes and then soldered from the opposite side of the board. While this method takes up more space, it provides superior mechanical strength and is often used for components that may endure mechanical stress.

This includes:

• Power connectors
• Transformers
• Large capacitors

Together, these mounting techniques enable manufacturers to meet a wide variety of design requirements for performance, durability, and size.

10. Soldering

Soldering is the process that permanently attaches electronic components to the circuit board by melting a metal alloy (solder) to form strong electrical and mechanical connections. The type of soldering used depends on the components and layout of the board.

Selective Soldering

Selective soldering uses a precise, localized stream or “bubble” of molten solder to attach components in specific areas, ideal for densely populated boards with a mix of surface-mount and through-hole parts.

This method allows for pinpoint accuracy, minimizing heat exposure to surrounding components and reducing the risk of bridging connections.

Wave Soldering

Wave soldering is commonly used for through-hole components. In this method, the underside of the board is passed over a flowing “wave” of molten solder that touches only the exposed leads and pads.

It’s efficient for soldering multiple joints at once and is well-suited for high-volume production.

11. Conformal Coating

Now that everything is in place, it is time to seal it with a coating to ensure longevity. This adds minimal thickness and weight while protecting all critical components.

12. Inspection and Testing

Rigorous quality checks are performed. This may include:

• Automated Optical Inspection (AOI) – for detecting defects like misaligned components.
• X-Ray Inspection – for verifying solder joints under large chips.
• Functional Testing – to confirm the board works as intended.

High-end boards may also go through burn-in testing to simulate heavy usage.

13. Final Cleaning, Packaging, and Shipping

The finished circuit board is cleaned to remove any flux residue or contaminants.

It’s then packaged in anti-static materials and shipped to computer manufacturers for integration into laptops, desktops, and servers.

Design and Manufacture Your PCB With Hallmark Nameplate

At Hallmark Nameplate, we specialize in Printed Circuit Board Assembly (PCBA) services tailored to your business requirements. With decades of experience and state-of-the-art equipment, we provide high-quality solutions for clients in healthcare, defense, consumer electronics, and beyond.

We’re here to guide you through every step, from design consultation to final assembly, ensuring that your computer circuit board meets all technical standards and performance goals.

Find the perfect solutions for your needs – request a FREE quote today!