The substrate of the PCB board itself is made of insulating and heat-insulating materials that are not easily bent. The small circuit material that can be seen on the surface is copper foil. Originally, the copper foil covered the entire PCB board, but part of it was etched away during the manufacturing process, and the remaining part became a network of small circuits. up. These lines are called wires or wiring, and are used to provide circuit connections to parts on the PCB. Usually the color of the PCB board is green or brown, which is the color of the solder resist paint. It is an insulating shield that protects the copper wires and also prevents parts from being soldered to incorrect places. Multi-layer boards are now used on motherboards and graphics cards, which greatly increases the area that can be wired. Multilayer boards use more single or double-sided wiring boards, and put an insulating layer between each layer of boards and then press them. The number of layers of the PCB board means that there are several independent wiring layers. Usually, the number of layers is even and includes the two outermost layers. Common PCB boards generally have a structure of 4 to 8 layers. The number of layers of many PCB boards can be seen by looking at the cut surface of the PCB board. But in reality, no one has such good eyesight. So, here's another way to teach you.
The circuit connection of the multi-layer board is through buried hole and blind hole technology. Most motherboards and display cards use 4-layer PCB boards, and some use 6-, 8-layer, or even 10-layer PCB boards. If you want to see how many layers the PCB has, you can identify it by observing the guide holes, because the 4-layer board used on the motherboard and display card is the first and fourth layers, and the other layers are used for other purposes (ground wires) and power supply). Therefore, like a double-layer board, the guide hole will penetrate the PCB board. If some guide holes appear on the front of the PCB but cannot be found on the back, then it must be a 6/8 layer board. If the same guide holes can be found on both sides of the PCB board, it is naturally a 4-layer board. Tips: Point the motherboard or display card to the light source, if the position of the guide hole can transmit light, it means that it is a 6/8-layer board; otherwise, it is a 4-layer board.
