It is able to detect the presence of nearby objects without any physical contact. A coil of wire is charged with electrical current, and an electronic circuit measures this circuit. If a metallic part gets close enough to the coil, the current will increase and the proximity switch will open or close accordingly.

It is available from 2mm to 20mm sensing distance. It is highly reliable with long functional life because of the absense of mechanical parts and lack of physical contact. It is available in two types NPN & PNP models, operates with 12 to 24 volt DC. It gives signal to PLC.