text: Proximity switches are used in industry to detect proximity of moving components. I am from aviation industry so I give example of landing gear down & locked condition sensing being done by proximity switches.The main parts of a proximity switch are the switch module & the target which do not come in contact with each other but come in close proximity. When the target comes in close proximity to the switch a signal is generated from the switch module for the appropriate circuit.\nThere are two distinct types of proximity switches;\nA) Magnetic type; Here the switch part of the module consists of an internal magnetically operated microswitch & the same is activated when a magnetic target comes in close proximity to it.\nB) Solid state type; The switch module consists of a gauss generating unit. When the non-magnetic target comes in close proximity to it the internal circuit is completed & a signal is generated.