PCB will appear in almost every electronic device. If there are electronic parts in a certain device, they are also embedded in PCB of different sizes. In addition to fixing a variety of small parts, the main function of the PCB is to provide the upper parts of the electrical connection. As electronic equipment becomes more complex, more and more parts are needed, and the circuits and parts on the PCB become denser and denser.
The board is made of insulating, non-bending material. The fine circuit material on the surface is copper foil, which is originally covered on the whole board, but it is etched away in the manufacturing process. The remaining part becomes a netlike small circuits. These lines are called conductor pattern, or layout; and they are used to provide electrical connections to parts on the PCB.
The green or brown color on the PCB is the color of the solder mask. This layer is insulated to protect copper wires and prevent parts from being welded incorrectly. Silk screen will be printed on the solder layer. Text and symbols (mostly white) are usually printed to indicate the location of each part on the board. Silk screen is also called legend.