Circuit board can be called printed circuit board or printed circuit board, PCB, FPC circuit board (FPC circuit board, also known as flexible circuit board) Flexible circuit board is a highly reliable, excellent flexible printed circuit board made of polyimide or polyester film as the substrate. With high wiring density, light weight, thin thickness, good bending characteristics), the birth and development of soft and hard combination board-FPC and PCB, gave birth to the new product of soft and hard combination board.

Therefore, the soft and hard combined board is the flexible circuit board and the hard circuit board, after pressing and other processes, according to the relevant process requirements combined together to form a circuit board with FPC characteristics and PCB characteristics.

The green part is called solder resistance, the composition is resin and pigment, the green is green color pigment, there are various other colors, and the decoration paint is no difference. Assembly welding is not printed on the circuit board before the paste can flow, printed on the circuit board, and finally to "cure", so that the resin is cured by heat. The purpose of solder resistance is to protect the circuit board from moisture, oxidation and dust. The only place that's not covered by the solder stop is usually called a pad for solder paste.

Another reason is that because the commonly used color is green, the spare green paint in the factory is the most, so the cost of oil is relatively low. And because in the maintenance of PCB board, different wiring is easier to distinguish the difference with white, and black and white are relatively difficult to see. In order to distinguish their own product grade, each factory uses two colors to distinguish the high-end series and the low-end series. For example, Asus, a company that does computer motherboards, yellow boards are low-end, and blackboards are high-end. The rebound of Yingtai is high-end, and the green board is low-end.

Generally, we choose green, because green is small to stimulate the eyes, production and maintenance personnel are not easy to eye fatigue when staring at PCB board for a long time to do business. Other commonly used colors are yellow, black and red. The colors are painted on the surface after it has been manufactured.

1, there are signs on the circuit board, R is the resistance, L is the inductor coil (usually the coil wrapped in the iron core ring, some have a closed shell), C is the capacitor (tall standing cylindrical, wrapped in plastic, there is a cross indentation above the electrolytic capacitor, flat is the chip capacitor), the other two legs of the diode, 3 legs of the triode, A lot of the legs are integrated circuits.

2, thyristor rectifier UR; Control circuit has a power supply rectifier VC; Inverter UF; Converter UC; Inverter UI; Motor M; Asynchronous motor MA; Synchronous motor MS; Dc motor MD; Wound-rotor induction motor MW; Squirrel cage motor MC; Electric valve YM; Solenoid valve YV, etc.