Visit：2058   Date：2019-12-26

A printed circuit board is a bare board—a circuit board without components on it.
The current circuit board mainly consists of the following
1. Circuit and Pattern: The circuit is used as a tool for the conduction between the originals. In design, a large copper surface will be designed as the ground and power layer. The lines and drawings are made at the same time.
2. Dielectric layer: It is used to maintain the insulation between the circuit and the layers, commonly known as the substrate.
3. Through hole (via): A via can make more than two levels of circuits communicate with each other, a larger via is used as a component plug-in, and a non-via (nPTH) is usually used as Surface mount positioning for fixing screws during assembly.
4, Solder resistant ink (Solder resistant / Solder Mask): Not all copper surfaces need to eat tin on parts, so non-tin-eating areas, will be printed on a layer of copper insulation material (usually epoxy) To avoid short circuit between non-tin-eating lines. According to different processes, it is divided into green oil, red oil, and blue oil.
5. Silk screen (Legend / Marking / Silk screen): This is an unnecessary structure. The main function is to mark the name and location frame of each part on the circuit board, which is convenient for maintenance and identification after assembly.

Extended information
The substrate of the printed circuit board itself is made of an insulating material that is not easily bent.
The small wiring material that can be seen on the surface is copper foil. Originally, the copper foil covered the entire board. During the manufacturing process, parts were etched away, and the remaining parts became small mesh networks. . These lines are called conductor patterns or wiring, and are used to provide electrical connections to parts on the PCB.
Usually the color of the PCB is green or brown, which is the color of the solder mask. It is an insulating protective layer that can protect copper wires, prevent short circuits caused by wave soldering, and save the amount of solder.
A silk screen is also printed on the solder mask. Usually text and symbols (mostly white) are printed on it to indicate the position of each part on the board. The screen printing surface is also called the legend surface.
When the final product is made, integrated circuits, transistors, diodes, passive components (such as resistors, capacitors, connectors, etc.) and various other electronic parts are installed on them. Through the wire connection, an electronic signal connection can be formed and there should be energy.