A switch refers to an electronic component that can open a circuit, interrupt current, or make it flow to other circuits. The principle of the switch is that the "closed" of the contact means that the electronic contact is conductive and current is allowed to flow; "open" means that the electronic contact is not conductive and forms an open circuit, and current is not allowed to flow.

According to the purpose, it is divided into wave switch, band switch, recording and playback switch, power switch, preselect switch, limit switch, etc. According to the structure, it is divided into micro switch, rocker switch, toggle switch, toggle switch, etc.