1. Printed circuit board definition:
PCB (Printed Circuit Board), the Chinese name is printed circuit board, also known as printed circuit board, is an important electronic component, a support body for electronic components, and a carrier for electrical connection of electronic components.
Because it is made using electronic printing, it is called a "printed" circuit board. PCB (printed circuit board) is a printed circuit board, referred to as a printed circuit board, is one of the important components of the electronics industry. Almost every electronic device, ranging from electronic watches and calculators to computers, communication electronic equipment, and military weapon systems, as long as there are electronic components such as integrated circuits, in order to make the electrical interconnection between the various components, use printed circuit boards. plate.
The printed circuit board consists of an insulating base plate, connecting wires and pads for assembling and soldering electronic components, and has the dual functions of a conductive circuit and an insulating base plate. It can replace complex wiring and realize the electrical connection between components in the circuit, which not only simplifies the assembly and welding of electronic products, reduces the workload of wiring in the traditional way, and greatly reduces the labor intensity of workers; it also reduces the size of the whole machine. volume, reduce product cost, and improve the quality and reliability of electronic equipment. The printed circuit board has good product consistency, and it can adopt standardized design, which is conducive to the realization of mechanization and automation in the production process. At the same time, the entire printed circuit board that has been assembled and debugged can be used as an independent spare part, which is convenient for the exchange and maintenance of the whole product. At present, printed circuit boards have been widely used in the production of electronic products
2. Types of printed circuit boards:
2.1 Single panel:
On the most basic PCB, the parts are concentrated on one side and the wires are concentrated on the other side. Because the wires only appear on one side, we call this type of PCB single-sided. This kind of board now generally uses silver as a bridge to realize the conduction of two lines. Because the single board has many strict restrictions on the design of the circuit (because there is only one side, the wiring cannot cross and must go around a separate path), so only early circuits used this type of board.
2.2 Double panel:
This board has wiring on both sides. However, to use two sides of the wire, there must be a proper circuit connection between the two sides. This kind of bridge between circuits is called a via hole. A via hole is a small hole on the PCB that is filled or coated with metal and can be connected to wires on both sides. Because the area of the double-sided board is twice as large as that of the single-sided board, and because the wiring can be interleaved (can be wound to the other side), it is more suitable for use on more complex circuits than single-sided boards.
2.3 Multilayer board:
In order to increase the area that can be wired, more single or double-sided wiring boards are used for multilayer boards. Multi-layer boards use several double-sided boards, and put an insulating layer between each board and then glue (press-fit). The number of layers of the board represents several independent wiring layers, usually the number of layers is even, and includes the outermost two layers. Typically 4, 6 or 8 layer boards.
2.4 High density board:
The vias just mentioned, if applied to a double-sided board, must be pierced through the entire board. However, in a multilayer board, if you only want to connect some of these traces, then vias may waste some trace space on other layers. Buried vias and blind vias technology can avoid this problem because they penetrate only a few of the layers. Blind via is to connect several layers of internal PCB with surface PCB,
