2A 3A 5A 25VAC push button mini electric 3 pin lever micro switch
The internals of a micro switch. Contacts, from left to right, are common, normally open, and normally closed.
A micro switch works by sensing movement or pressure from its surroundings. For example, when the dishwasher opens it takes pressure off an actuator, also known in Laymen’s terms, as a button or plunger . When the pressure is taken off of this button it opens a circuit. This means the electricity is cut off from the rest of the machine
In operation, micro switches exhibit hysteresis. Wikipedia defines hysteresis as “the dependence of the output of a system not only on its current input, but also on its history of past inputs. The dependence arises because the history affects the value of an internal state.”
In micro switches, it’s easiest to think of it like this. When the actuator is depressed, there is a point at which the switch activates, connecting the Common contact to the normally open (NO) contact. As pressure on the actuator decreases, the point at which the switch reverts to its non-activated state, with the Common contact falling back onto the normally closed (NC) contact, is not the same as the activation point, it’s later. The distance between the actuating point and the release point is called differential movement, or hysteresis.
Common applications of micro switches include the door interlock on a microwave oven, levelling and safety switches in elevators, vending machines,