PCB News - Classification of single-sided, double-sided, and multilayer circuit boards

Classification of single-sided, double-sided, and multilayer circuit boards

1, single-sided circuit board

We call PCB as single-sided. Because single-sided boards have many strict restrictions on the design of the circuit (because there is only one side, the wiring cannot be crossed and must be routed independently), so only early circuits use this type of board.

2, double-sided circuit board

This kind of circuit board has wiring on both sides. However, to use wires on both sides, there must be a proper circuit connection between the two sides. This kind of "bridge" between circuits is called a via. A via is a small hole filled or coated with metal on the PCB, which can be connected with the wires on both sides. Because the area of the double-sided circuit board is twice as large as that of the single-sided PCB board, and because the wiring can be interleaved (it can be wound to the other side), it is more suitable for use in circuits that are more complicated than the single-sided PCB board.

3, multilayer circuit board

When a multi-layer circuit board is required for more complex applications, the circuit can be arranged in a multi-layer structure and pressed together, and through-hole circuits are arranged between layers to connect the circuits of each layer. In order to increase the area that can be wired, more Layer circuit boards use more single or double-sided wiring boards. The multi-layer circuit board uses several double-sided circuit boards, and an insulating layer is placed between each layer of the PCB multi-layer circuit board and then glued (compressed) firmly. The number of layers of the PCB board means that there are several independent wiring layers, usually the number of layers is even, and contains the two outermost layers. Most motherboards are 4-layer to 8-layer structure, but technically it can be nearly 100-layer PCB board. Most large supercomputers use fairly multi-layer motherboards, but because these types of computers can already be replaced by clusters of many ordinary computers, super-multilayer circuit boards are gradually not being used. Because the layers in the PCB multilayer circuit board are tightly integrated, it is generally not easy to see the actual number, but if you look closely at the motherboard, you may be able to see it.