A push-button or simply button is a simple switch mechanism to control some aspect of a machine or a process. Buttons are typically made out of hard material, usually plastic or metal. The surface is usually flat or shaped to accommodate the human finger or hand, so as to be easily depressed or pushed.

What is a momentary switch used for?

Momentary switches are used on heavy duty roller doors; the operator must old down the switch when the door is opening or closing, if there are any obstructions to the doorway, the operator can quickly stop the door from closing preventing an accident.

What is an example of a momentary switch?

A momentary switch is a "spring return" switch which automatically returns to its original or at rest position. A simple example of a momentary switch would be a doorbell, which automatically returns back to its resting "OFF" position when no longer actuated.