The definition of printed circuit board and its classification

Printed circuit boards, also known as printed circuit boards, are providers of electrical connections for electronic components.
The printed circuit board is mostly represented by “PCB”, but cannot be called “PCB board”.
The design of printed circuit boards is mainly layout design; the main advantage of using circuit boards is to greatly reduce wiring and assembly errors, and improve the automation level and production labor rate.
Printed circuit boards can be divided into single-sided, double-sided, four-layer, six-layer and other multi-layer circuit boards according to the number of circuit boards.
Since the printed circuit board is not a general end product, the definition of the name is slightly confusing. For example, the motherboard for personal computers is called the motherboard, but not directly called the circuit board. Although there are circuit boards in the motherboard, but They are not the same, so the two are related but cannot be said to be the same when assessing the industry. Another example: because there are integrated circuit parts loaded on the circuit board, the news media calls it an IC board, but in fact it is not the same as a printed circuit board. When we usually speak of a printed circuit board, we mean a bare board – that is, a circuit board with no components on it.

Classification of printed circuit boards

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, this kind of PCB is called a single-sided (Single-sided). Because single-sided boards have many strict constraints on designing wiring (because there is only one side, wiring cannot cross and must go around separate paths), only early circuits used this type of board.

Double panel
This circuit board has wiring on both sides, but to use both sides of the wire, there must be a proper circuit connection between the two sides. Such “bridges” between circuits are called vias. Vias are small holes on a PCB, filled or painted with metal, that 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, the double-sided board solves the difficulty of interleaving the wiring in the single-sided board (it can be passed to the other side through the via hole), and it is more suitable for use in more complex circuits than the single-sided board.

Multilayer board
In order to increase the area that can be wired, more single or double-sided wiring boards are used for multilayer boards. A printed circuit board with a double-sided inner layer, two single-sided outer layers, or two double-sided inner layers and two single-sided outer layers, alternated together by a positioning system and insulating bonding materials, and conductive patterns. Printed circuit boards that are interconnected according to design requirements become four-layer and six-layer printed circuit boards, also known as multi-layer printed circuit boards. The number of layers of the board does not mean that there are several independent wiring layers. In special cases, an empty layer will be added to control the thickness of the board. Usually, the number of layers is even and includes the outermost two layers. Most motherboards are 4 to 8 layers of structure, but technically it can achieve nearly 100 layers of PCB. Most large supercomputers use fairly multi-layer motherboards, but because such computers can be replaced by clusters of many ordinary computers, ultra-multi-layer boards have gradually fallen out of use. Because the layers in the PCB are tightly combined, it is generally not easy to see the actual number, but if you look closely at the motherboard, you can still see it.