PCB

PCB (printed circuit board), also known as printed circuit board in Chinese, is an important electronic component, the support of electronic components, and the carrier of electrical interconnection of electronic components. Because it is made by electronic printing, it is called "printed" circuit board. [1]

Printed circuit board (PCB) is one of the important components of electronic industry. Almost every kind of electronic equipment, ranging from electronic watches and calculators to computers, communication electronic equipment and military weapon systems, needs to use printed boards in order to electrically interconnect various components as long as there are electronic components such as integrated circuits. The printed circuit board is composed of an insulating base plate, connecting wires and bonding pads for assembling and welding electronic components, and has dual functions of conductive lines and insulating base plates. It can replace the complex wiring and realize the electrical connection between the components in the circuit. It not only simplifies the assembly and welding of electronic products, but also reduces the wiring workload in the traditional way and greatly reduces the labor intensity of workers; It also reduces the volume of the whole machine, reduces the product cost, and improves the quality and reliability of electronic equipment. The printed circuit board has good product consistency. It can adopt standardized design, which is conducive to mechanization and automation in the production process. At the same time, the whole printed circuit board that has been assembled and debugged can be used as an independent spare part to facilitate the exchange and maintenance of the whole machine. At present, printed circuit boards have been widely used in the production of electronic products. [2] 
The earliest printed circuit board was paper-based copper-clad printed circuit board. Since the appearance of semiconductor transistors in the 1950s, the demand for printed boards has risen sharply. Especially with the rapid development and wide application of integrated circuits, the volume of electronic equipment is getting smaller and smaller, and the density and difficulty of circuit wiring are getting larger and larger, which requires that printed boards be constantly updated. At present, the variety of printed boards has developed from single panel to double-sided board, multilayer board and flexible board; The structure and quality have also developed to ultra-high density, miniaturization and high reliability; New design methods, design supplies, board making materials and board making processes are constantly emerging. In recent years, various application software of computer-aided design (CAD) printed circuit board has been popularized and promoted in the industry. Among specialized printed circuit board manufacturers, mechanized and automated production has completely replaced manual operation. [2]