Limit switch
![A limit switch with a roller-lever operator; this is installed on a gate on a canal lock, and indicates the position of a gate to a control system.](/Images/godic/202501/24/Eindschakelaar_op_de_Mallegatsluis_in_Gouda4719.JPG")
![A limit switch mounted on a moving part of a bridge.](/Images/godic/202501/24/A_detail_of_the_Cherry_Street_Straus_Bascule_bridge,_from_flickr_-a4719.jpg")
In electrical engineering a limit switch is a switch operated by the motion of a machine part or presence of an object.
They are used for controlling machinery as part of a control system, as a safety interlocks, or to count objects passing a point. A limit switch is an electromechanical device that consists of an actuator mechanically linked to a set of contacts. When an object comes into contact with the actuator, the device operates the contacts to make or break an electrical connection.