Roller Lever Micro Switch 3 Terminal SPDT Momentary Limit Switch

A limit switch is a small switch that a moving part presses, so a circuit knows something has reached a particular position. The Roller Lever Micro Switch – SPDT Limit Switch does this with a durable metal roller on the end of its lever. A cam, arm or door edge rolls over the roller instead of dragging across it, which reduces friction and wear when it is triggered again and again.

Wiring the three terminals

SPDT (single pole, double throw) means one shared contact that connects to one of two others:

• COM – common, the shared connection
• NO – normally open, so the circuit closes when the lever is pressed
• NC – normally closed, so the circuit opens when the lever is pressed

Use COM and NO if something should switch on at the end of travel. Use COM and NC if it should cut off.

The action is momentary: the lever springs back when released and the switch does not latch. The internal snap-action mechanism gives a consistent switching point and an audible, tactile click.

Where it suits

Door position sensing, limit detection on moving assemblies, machine control panels, arcade controls, robotics and hobby electronics. It is intended for low-voltage control circuits and embedded systems.

Check before you buy

• A moving part must be able to reach the roller and push the lever.
• Your circuit should be low-voltage.
• The compact body is made for panel or device installation, so make sure you have room to mount it where the lever will be contacted.