PCB (Printed Circuit Board), the Chinese name is printed circuit board, also known as printed circuit board, is an important electronic component, a support for electronic components, and a carrier for electrical connection of electronic components. Because it is made by electronic printing, it is called a "printed" circuit board. The printed circuit board is an assembly board where mounting holes are drilled in a predetermined position on the insulating substrate, and soldering electronic components and connecting wires are placed to realize the electrical connection between the components, so that the circuit board can realize the expected design function .

The PCB circuit board not only provides mechanical support, but also connects the components mounted on it. Therefore, for the designer of the printed circuit board, it is necessary to understand the entire physical size of the panel (outer frame size), the location of the mounting hole, the height limit and related details.

The reason why PCB can be used more and more widely is that it has many unique advantages, which are summarized as follows.

Can be high-density: For decades, the high-density of printed boards has been able to develop along with the improvement of integrated circuit integration and the advancement of mounting technology.

High reliability: Through a series of inspections, tests and aging tests, the PCB can work reliably for a long time (usually 20 years).

Designability: For PCB performance (electrical, physical, chemical, mechanical, etc.) requirements, printed board design can be achieved through design standardization, standardization, etc., with short time and high efficiency.

Manufacturability: With modern management, it can be standardized, scaled (quantified), automated, etc., to ensure product quality consistency.

Testability: A relatively complete test method, test standard, various test equipment and instruments have been established to detect and appraise the eligibility and service life of PCB products.

Assemblability: PCB products are not only convenient for standardized assembly of various components, but also for automated and large-scale mass production. At the same time, PCB and various component assembly parts can be assembled to form larger parts and systems, up to the complete machine.

Maintainability: As PCB products and various component assembly parts are standardized and produced on a large scale, these parts are also standardized. Therefore, once the system fails, it can be replaced quickly, conveniently and flexibly, and the system can be quickly restored to work. Of course, there can be more examples. Such as miniaturization and weight reduction of the system, and high-speed signal transmission.