A proximity switch is a position switch that does not require direct mechanical contact with moving parts. When an object approaches the sensing surface of the switch to a certain distance, the switch can be activated, thereby driving DC electrical appliances or providing control instructions to computer (PLC) devices. A proximity switch is a switch type sensor (i.e. a contactless switch) that combines the characteristics of a travel switch and a micro switch, as well as sensing performance. It has reliable action, stable performance, fast frequency response, long application life, strong anti-interference ability, and is waterproof and corrosion-resistant. The products include inductive, capacitive, Hall, AC, and DC types.