A push switch is an electrical switch that must be pushed and held to make or break a circuit. When the user releases the switch, it springs back to the prior position. This is an example of a non-latching switch. Unlike a simple light switch in a wall, which remains in whatever position the user left it in, the push switch always returns back to a set point when released. Such switches can be useful for a variety of applications.
In some cases, the user must push and hold the switch to activate a circuit. This can be useful in some manufacturing settings, where it might be advisable to have an operator hold a switch down to turn a circuit on. This limits the chance of accidental activations or situations where switches are left on, because someone has to be present at the switch for the circuit to be live.
Another use for this kind of push switch can be in a research experiment, where the researcher might need someone to touch a switch upon hearing a tone or seeing something. A push switch can be used so it will pop back when the subject releases it, giving a single reading each time the subject activates the switch. The switch can also link to a device to record the number of pushes and the timing, so the researcher can later link it up with the experimental conditions.
Other push switches operate in an always on position, where someone needs to activate the switch to turn it off, and hold it to keep the circuit off. There may be settings in which the default for a circuit should be on, as with a security system. This type of push switch breaks the circuit when pushed in, and springs back to close the circuit when the operator releases the switch.
It is possible to replace a variety of switch designs with a push switch, since the basic wiring is the same as for other switch types. People can also change the function of a push switch from always on to always off by changing the wiring, if this becomes necessary. In some settings, the electrical and safety code may require the use of this type of switch to keep workers and bystanders safer in hazardous environments. At a paper cutter, for example, there may be a recessed push switch that must be held down to operate the device to reduce the risk of accidents.