You're sure to find printed circuit boards in almost all electronic devices. From radios, televisions, smartphones, LED lights to computers.

　　In any electronic device, circuit boards help receive or send signals. But how do circuit boards work? What are the roles of various PCB components such as transistors, diodes, resistors, and capacitors?

　　This guide provides details to help answer questions such as how PCBs work and what circuit boards do.

　　 What is a circuit board?

　　A circuit board is a flat, non-conductive material used to house different electronic components connected by interconnected paths called traces. Circuit boards can be single-sided, double-sided, or multi-layered.

　　 How does a circuit board work?

　　Circuit boards allow electrical signals to flow from one component to the next through specific conductive paths (called traces).

　　Signal flow helps receive, transmit signals, or convert signals into mechanical functions. Understanding how a circuit board works is easy if you know the components that make up the power board.

　　 Components of a circuit board

　　Understanding how a PCB works is only possible after understanding its components. Each mechanical and electrical device on the circuit board plays a different role. These include:

　 　Transistors

　　A transistor is a semiconductor device that plays a crucial role in a circuit board. It helps amplify electronic signals or act as a signal control switch.

　　The amplified signal then passes through the traces and switches on another high-power semiconductor device. Transistors on a circuit board are of PNP or NPN type.

　 　Resistors

　　Another important component of a circuit board is the resistor. The role of a resistor is to regulate the amount of current flowing through a device.

　　As current flows through the resistor, the device dissipates heat, thereby regulating the current. They come in two types: fixed and variable. On a printed circuit board, the symbol for a resistor is the letter R.

　　 Capacitors

　　The symbol for a capacitor is the letter C. A capacitor stores charge in an electrostatic field for a period of time. It then releases a large amount of electricity by discharging at the appropriate time. One widespread use of a capacitor is to smooth out the ripple of rectified AC electricity.

　 　Diodes

　　A diode is a semiconductor device that conducts current in only one direction. They vary in size and the amount of current they can safely carry without failing.

　　The unidirectional nature of diodes makes them ideal for rectifying alternating current (AC) to direct current (DC). One famous diode is the light-emitting diode (LED). As the name suggests, an LED emits light when current passes through it.

　　 Inductors

　　An inductor is another common component on a circuit board. An inductor stores current in a magnetic field. In most cases, inductors are used with capacitors to form an LC circuit.

　　 Transformers

　　Transformers have electromagnetic properties. The role of a transformer is to regulate the transfer of energy from one part of a circuit board to another. In this process, it isolates one part of the circuit board and protects sensitive devices. Transformers can increase or decrease power in a circuit as needed.

　　 Switches

　　A switch allows current to flow when it is in the ON position. However, when the switch is in the OFF position, it cuts off the current flowing through the circuit board.

　　 Integrated Circuits (ICs)

　　Integrated circuits are commonly known as ICs. As the name suggests, ICs contain a large number of circuits with miniature components integrated into them. Another name for ICs is microchips, and they play multiple roles in circuit boards.

　　 Types of Printed Circuit Boards

　　Single-sided (Single-layer)

　　Single-layer PCBs are also known as single-sided circuit boards. This type of circuit board is easy to find and affordable. In addition, single-sided PCBs have a conductive copper layer on one side and the other side is the layout of electronic components.

　　While single-sided circuit boards are low in production cost, they also have some limitations. Therefore, it is not a good choice for high-end applications.

　　 Double-sided

　　Double-sided circuit boards are also known as double-layer PCBs. Like single-sided circuit boards, double-sided circuit boards also have only one substrate. However, its core material has a thin layer of conductive material on both sides of the circuit board.

　　In addition, double-sided circuit boards also use surface mount and through-hole technology. In this way, the circuits on both sides can be connected through plated through-holes. The role of this circuit board is to allow components to be mounted on two surfaces.

　　The introduction of double-layer technology has enabled circuit boards to handle more complex applications than before.

　　 Multilayer

　　Unlike single-layer or double-layer PCBs, multilayer circuit boards use multiple substrate materials. In other words, it is a circuit board that combines three or more double-sided PCBs into one unit.

　　Therefore, in real life, you can find four-layer, six-layer, eight-layer, twelve-layer, and even more layers of PCBs on the board. In multilayer circuit boards, electronic components are only located on the top and bottom layers. All other stacked units help with wiring.

　　Multilayer circuit boards have high component density, many circuits, and small footprint, so they are often used in computers, GPS, satellites, aerospace systems, etc.

　　Note that multilayer circuit boards have high design requirements, high manufacturing costs, and are difficult to repair.

　 　Flexible Circuits

　　As the name suggests, flexible circuits are flexible and therefore foldable. Flexible PCBs can be single-layer, double-layer, or multi-layer. Its significant feature is its flexibility. Flexible printed circuit boards use soft substrate materials such as thin plastic, polyimide, or Kapton.

　　A prominent advantage of flexible printed circuit boards is their ease of handling and tolerance of extreme temperatures. Due to their flexibility, PCBs can conform to the shapes of various electronic devices.

　　 Rigid Circuit

　　Unlike flexible circuits, rigid circuit boards lack flexibility. Rigid printed circuit boards use inflexible substrate materials. Therefore, once the board is designed and manufactured, its shape cannot be altered.

　　Rigid circuit boards offer excellent strength and durability. Computer motherboards are a typical example of rigid PCBs. Note that circuit boards can have any number of layers.

　　 Rigid-Flex

　　Rigid-flex printed circuit boards are a hybrid of flexible and rigid boards. By combining these two types of boards, rigid-flex PCBs are both flexible and durable.

　　 High-Frequency

　　High-frequency printed circuit boards are suitable for circuits that require fast data processing and high frequencies. Sometimes, such circuits process data at speeds up to 2 gigahertz. Such circuit boards are found in networking equipment, radios, microwave ovens, and mobile phones.

　　 Aluminum-backed PCB

　　Aluminum-backed PCBs use thick aluminum metal as the core material. However, aluminum-backed boards have a dielectric top layer and a thick conductive copper layer.

　　Due to their design, aluminum-backed circuit boards are robust, have good heat dissipation, and can handle high currents. Some of their typical applications are LED lighting, the automotive industry, and power supplies.

　　 Conclusion

　　Circuit boards in modern electronic devices vary in size. But the working principle of the circuit board is the same. Whether it is a single-layer, double-layer, or multilayer board, it relies on various electronic components to perform its function.