The printed circuit board (PCB) is a physical basis or a platform on which electronic components can be soldered. Copper traces connect these components to each other, allowing the printed circuit board (PCB) to perform its functions in the manner designed.

The printed circuit board is the core of the electronic device. It can be of any shape and size, depending on the application of the electronic device. The most common substrate/substrate material for PCB is FR-4. FR-4 based PCBs are commonly found in many electronic devices, and their manufacturing is common. Compared with multilayer PCBs, single-sided and double-sided PCB are easier to manufacture.

FR-4 PCB is made of glass fiber and epoxy resin combined with laminated copper cladding. Some of the main examples of complex multi-layer (up to 12 layers) PCBs are computer graphics cards, motherboards, microprocessor boards, FPGAs, CPLDs, hard drives, RF LNAs, satellite communications antenna feeds, switch mode power supplies, Android phones, etc. There are many examples where simple single-layer and double-layer PCBs are used, such as CRT TVs, analog oscilloscopes, handheld calculators, computer mice, and FM radio circuits.

Application of PCB:

1. Medical equipment:

Today’s advancement in medical science is entirely due to the rapid growth of the electronics industry. Most medical equipment, such as pH meter, heartbeat sensor, temperature measurement, ECG/EEG machine, MRI machine, X-ray, CT scan, blood pressure machine, blood sugar level measuring equipment, incubator, microbiological equipment and many other equipment It is a separate electronic PCB based. These PCBs are generally dense and have a small form factor. Dense means that smaller SMT components are placed in a smaller size PCB. These medical devices are made smaller, easy to carry, light in weight, and easy to operate.

2. Industrial equipment.

PCBs are also widely used in manufacturing, factories, and looming factories. These industries have high-power machinery and equipment that are driven by circuits that operate at high power and require high currents. For this reason, a thick copper layer is laminated on the PCB, which is different from complex electronic PCBs, which can draw currents as high as 100 amperes. This is particularly important in applications such as arc welding, large servo motor drives, lead-acid battery chargers, military industry, and clothing cotton vague machines.

3. illumination.

In terms of lighting, the world is moving in the direction of energy-saving solutions. These halogen bulbs are rarely found now, but now we see LED lights and high-intensity LEDs around. These small LEDs provide high-brightness light and are mounted on PCBs based on aluminum substrates. Aluminum has the property of absorbing heat and dissipating it in the air. Therefore, due to high power, these aluminum PCBs are usually used in LED lamp circuits for medium and high power LED circuits.

4. Automotive and aerospace industries.

Another application of PCB is the automotive and aerospace industries. The common factor here is the reverberation generated by the movement of airplanes or cars. Therefore, in order to satisfy these high-force vibrations, the PCB becomes flexible. Therefore, a kind of PCB called Flex PCB is used. The flexible PCB can withstand high vibration and is light in weight, which can reduce the total weight of the spacecraft. These flexible PCBs can also be adjusted in a narrow space, which is also a great advantage. These flexible PCBs are used as connectors, interfaces, and can be assembled in a compact space, such as behind the panel, under the dashboard, etc. A combination of rigid and flexible PCB is also used.

PCB type:

Printed circuit boards (PCB) are divided into 8 categories. They are

Single-sided PCB:

The components of a single-sided PCB are only mounted on one side, and the other side is used for copper wires. A thin layer of copper foil is applied to one side of the RF-4 substrate, and then a solder mask is applied to provide insulation. Finally, screen printing is used to provide marking information for components such as C1 and R1 on the PCB. These single-layer PCBs are very easy to design and manufacture on a large scale, the market demand is large, and they are also very cheap to buy. Very commonly used in household products, such as juicers/blenders, charging fans, calculators, small battery chargers, toys, TV remote controls, etc.

Double-layer PCB:

Double-sided PCB is a PCB with copper layers applied on both sides of the board. Drill holes, and THT components with leads are installed in these holes. These holes connect one side part to the other side part through copper tracks. The component leads pass through the holes, the excess leads are cut by the cutter, and the leads are welded to the holes. All this is done manually. There are also SMT components and THT components of a 2-layer PCB. SMT components do not need holes, but pads are made on the PCB, and the SMT components are fixed on the PCB by reflow soldering. SMT components occupy very little space on the PCB, so more free space can be used on the circuit board to achieve more functions. Double-sided PCBs are used for power supplies, amplifiers, DC motor drivers, instrument circuits, etc.

Multilayer PCB:

Multi-layer PCB is made of multi-layer 2-layer PCB, sandwiched between dielectric insulating layers to ensure that the board and components are not damaged by overheating. Multi-layer PCB has various dimensions and different layers, from 4-layer PCB to 12-layer PCB. The more layers, the more complicated the circuit and the more complicated the PCB layout design.

Multi-layer PCBs usually have independent ground planes, power planes, high-speed signal planes, signal integrity considerations, and thermal management. Common applications are military requirements, aerospace and aerospace electronics, satellite communications, navigation electronics, GPS tracking, radar, digital signal processing and image processing.

Rigid PCB:

All the PCB types discussed above belong to the rigid PCB category. Rigid PCBs have solid substrates such as FR-4, Rogers, phenolic resin and epoxy resin. These plates will not bend and twist, but can maintain their shape for many years for up to 10 or 20 years. This is why many electronic devices have a long lifespan because of the rigidity, robustness and rigidity of rigid PCBs. The PCBs of computers and laptops are rigid. Many TVs, LCD and LED TVs commonly used in homes are made of rigid PCBs. All of the above single-sided, double-sided and multilayer PCB applications are also applicable to rigid PCBs.

Flex PCB:

Flexible PCB or flexible PCB is not rigid, but it is flexible and can be bent easily. They are elastic, have high heat resistance and excellent electrical properties. The substrate material of Flex PCB depends on performance and cost. Common substrate materials for Flex PCB are polyamide (PI) film, polyester (PET) film, PEN and PTFE.

The manufacturing cost of Flex PCB is more than just rigid PCB. They can be folded or wrapped around corners. Compared with the corresponding rigid PCB, they take up less space. They are lightweight but have very low tear strength.

Rigid-Flex PCB:

The combination of rigid and flexible PCBs is very important in many space and weight-constrained applications. For example, in a camera, the circuit is complicated, but the combination of rigid and flexible PCB will reduce the number of parts and reduce the PCB size. The wiring of two PCBs can also be combined on a single PCB. Common applications are digital cameras, mobile phones, cars, laptops and those devices with moving parts

High-speed PCB:

High-speed or high-frequency PCBs are PCBs used for applications involving signal communication with frequencies higher than 1 GHz. In this case, signal integrity issues come into play. The material of the high-frequency PCB substrate should be carefully selected to meet the design requirements.

Commonly used materials are polyphenylene (PPO) and polytetrafluoroethylene. It has a stable dielectric constant and small dielectric loss. They have low water absorption but high cost.

Many other dielectric materials have variable dielectric constants, resulting in impedance changes, which can distort harmonics and loss of digital signals and loss of signal integrity

Aluminum PCB:

Aluminum-based PCBs substrate materials have the characteristics of effective heat dissipation. Due to low thermal resistance, aluminum-based PCB cooling is more effective than its corresponding copper-based PCB. It radiates heat in the air and in the thermal junction area of ​​the PCB board.

Many LED lamp circuits, high-brightness LEDs are made of aluminum backing PCB.

Aluminum is a rich metal and its mining price is low, so the cost of PCB is also very low. Aluminum is recyclable and non-toxic, so it is environmentally friendly. Aluminum is strong and durable, so it reduces damage during manufacturing, transportation and assembly

All these features make aluminum-based PCBs useful for high-current applications such as motor controllers, heavy-duty battery chargers, and high-brightness LED lights.

in conclusion:

In recent years, PCBs have evolved from simple single-layer versions to more complex systems, such as high-frequency Teflon PCBs.

PCB now covers almost every field of modern technology and evolving science. Microbiology, microelectronics, nanotechnology, aerospace industry, military, avionics, robotics, artificial intelligence and other fields are all based on various forms of printed circuit board (PCB) building blocks.