The Mysteries of Circuit Boards: From Materials to Working Principles and Types

How Do Circuit Boards Work?

Circuit boards are the heart of modern electronic devices. Whether it’s your phone, computer, or microwave at home, they all rely on the support of circuit boards. These seemingly inconspicuous small boards are actually composed of complex materials and circuits, responsible for connecting and controlling various electronic components, allowing the entire device to function properly. Next, we will delve into the composition, working principles, and different types of circuit boards.

What Are Circuit Boards Made Of?

Circuit boards are composed of multiple layers of materials, each with specific functions. The main components include:

  1. Substrate Material: The most commonly used material is FR4, a glass fiber-reinforced epoxy resin. It is lightweight, durable, and provides good mechanical strength and insulation properties.
  2. Copper Foil: The copper foil covering the substrate forms the circuit patterns. The copper foil is usually very thin, typically in the range of a few micrometers thick.
  3. Solder Mask: This green coating covers the copper foil to prevent oxidation and short circuits.
  4. Silkscreen Layer: Used to mark the positions and numbers of components, facilitating assembly and maintenance.

Basic Components of Circuit BoardsCircuit Board Assembly

Printed Circuit Boards (PCBs) are used to support and connect electronic components. They can have one or more layers, each covered with conductive copper foil. The primary function of PCBs is to provide a stable mounting position for electronic components and to connect them through copper tracks, allowing current to flow between components and drive them to perform various functions. Let’s see how some common electronic components work in the circuit.

Resistors

Resistors limit the flow of current, controlling the voltage and current in the circuit. They work by converting a portion of electrical energy into heat, thereby reducing the speed and intensity of current flow. The resistance value of a resistor determines its level of impedance to the current.

Capacitors

Capacitors store and release electrical energy and can smooth voltage fluctuations and filter noise in circuits. They consist of two conductive plates separated by an insulating material (dielectric). When current flows through, charges accumulate on the conductive plates, storing electrical energy.

Transistors

Transistors are semiconductor devices used to amplify and switch electronic signals. They are fundamental components in modern electronic devices, widely used in amplifiers, power management, and digital circuits. By controlling the current at the base, transistors can regulate the current flowing through the collector and emitter, thereby achieving signal amplification and switching functions.

Types of Printed Circuit Boards

PCBs are critical components used in various electronic products. Initially invented for military purposes, they are now widely used in radios, gadgets, machines, and even our phones and computers. To understand how these circuit boards work, we must comprehend their manufacturing process. Common materials used in PCB manufacturing include G10 materials or FR4 grade glass fiber-reinforced epoxy resin, often combined with Teflon. However, not all types of PCBs are suitable for the mentioned applications. There are multiple types of circuit boards, each with its unique advantages and application scen

Single-Sided PCBs

arios. Here are some common types of circuit boards:

Single-Sided PCBs

Single-sided PCBs have the circuit pattern on only one side of the board. They are simple and inexpensive to manufacture, making them suitable for low-density designs.

Double-Sided PCBs Double-sided-PCB

Double-sided PCBs have copper foil patterns on both sides of the board. This design allows for more complex circuit layouts and the placement of more electronic components on the same board. Double-sided PCBs are commonly used in household electronic devices, automotive electronics, and communication equipment.

Multi-Layer PCBsMulti-Layer PCBs

Multi-layer PCBs combine two or more double-sided circuits into one PCB. These boards can have 4, 6, 8, or even 12 layers, with different components on all layers. They are widely used in almost all types of electronic devices. Surface mount and through-hole technologies are used to connect components to the metal layers in these PCBs.

Rigid PCBs

Rigid PCBs are made from sturdy substrate materials, providing strength and durability. They are used in various applications, including the aerospace industry and advanced military technology. Rigid PCBs are usually made from thermoplastic materials and do not bend or flex, unlike flexible PCBs. They are manufactured by laminating layers of copper and insulation materials onto a substrate, typically made of fiberglass.

Flexible PCBs

Flexible PCBs are similar to circuit boards but are made from more flexible materials than other types of printed circuit boards. These circuits are often used in small components, particularly suitable for interconnecting simple electronic devices. Flexible PCBs are very flexible and can withstand extremely high temperatures.

Rigid-Flex PCBsRigid-Flex PCBs

Rigid-flex PCBs combine the advantages of rigid PCBs and flexible circuit boards, having both rigid and flexible parts on the same board. They are suitable for electronic devices that require high density and multifunctionality, such as modern smartphones and portable electronic devices.

High-Frequency PCBs

High-frequency PCBs are designed to handle high-frequency signals, commonly used in wireless communication devices and high-speed computer networks. They use special materials and designs to ensure stable operation in high-frequency environments, reducing signal interference and loss.

Aluminum-Backed PCBs

Aluminum-backed PCBs incorporate a layer of aluminum foil in the substrate material for heat dissipation management. They are mainly used in high-power LED lighting and power electronics, effectively dissipating heat and extending the lifespan of electronic components.

Circuit board design

The design and layout of printed circuit boards (PCBs) is a complex process that requires meticulous planning and precise design. This process not only demands optimization of circuit performance but also necessitates the arrangement of electrical connections in a manner that minimizes size and cost.

Schematic Design

The first step in designing a PCB is to create the schematic. This is a symbolic representation of the circuit, showing components and their electrical connections without depicting their physical layout. The schematic serves as the blueprint of the circuit, detailing the electrical relationships between components. Ensuring all connections are correct and complete at this stage is crucial to avoid potential issues in subsequent steps.Circuit board design

Physical Layout Design

The next step is the physical layout design, which involves placing the components on the PCB and arranging their electrical connections. The goal is to minimize connection lengths and avoid cross paths, thereby reducing interference and signal loss.

This is typically achieved using Computer-Aided Design (CAD) software. CAD tools allow designers to place components and route connections in a virtual environment, making it easier to visualize and adjust the layout as needed. Additionally, CAD software can perform design rule checks to ensure the layout adheres to specific standards, such as minimum spacing between components.

Balancing and Optimization

During the layout process, designers must balance performance and size. A compact layout can save space and reduce costs but may result in higher density electrical paths, increasing the risk of interference. Conversely, a more dispersed layout can reduce interference and enhance performance but may increase the size and cost of the PCB.

For certain high-performance circuits, multi-layer PCB designs may be necessary to ensure efficiency and consistent performance. Multi-layer designs allow the distribution of signals and power across different layers, further optimizing performance and reducing interference.

Considerations for Manufacturing and Cost

Designers must also consider manufacturing processes and costs. Selecting appropriate materials, the number of layers, and manufacturing techniques can significantly impact the final performance and cost of the PCB. The use of High-Density Interconnect (HDI) technology and microvia techniques can further increase the integration and performance of the PCB.

Conclusion

Circuit boards, as the core of modern electronic devices, come in various types, each with its unique advantages and application scenarios. From simple single-sided PCBs to complex multi-layer PCBs, from rigid PCBs to flexible circuit boards, the design and manufacturing of each type of circuit board require precise craftsmanship and technical support. Understanding the working principles and types of these circuit boards not only helps us use electronic devices better but also provides a deeper understanding of the development of modern technology.If you want to know more about the article, you can contact us and we can give you a more detailed answer.