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Visit：14070   Date：2019-12-26

1. L stands for lamp, and it can also mean left.
2. M stands for motor or mega, M = DC positive output, M- = DC negative input;
3. S indicates that the switch can also indicate conductivity.
4. SW indicates the circuit board type or gear switch.

Extended information:
Printed boards have evolved from single-layer to double-sided, multilayer, and flexible, and still maintain their own development trends. Due to the continuous development of high precision, high density and high reliability, and continuous reduction in size, cost and performance, printed boards still maintain a strong vitality in the future development of electronic equipment.
Single-layer board: On the most basic printed circuit board, parts are concentrated on one side, and wires are concentrated on the other side. Because the wires only appear on one side, the pcb is called a single-sided circuit board.
Double-sided board: It is an extension of single-layer board. When single-layer wiring cannot meet the needs of electronic products, double-layer wiring should be used, with copper-clad wires on both sides. Through-holes can guide the wires between the two layers to form the required network connection.
Multilayer board: refers to a printed board with more than three conductive pattern layers and insulating materials laminated between them, and the conductive patterns between them are interconnected as required.