This paper discusses the options a circuit designer has to turn on and off supply lines in electronic systems. While the task sounds trivial, there are many things to consider for a successful implementation.

In some electrical systems, disconnecting a supply line is necessary. This may be in the form of cutting off a battery voltage to retain the battery charge or separating a load from a live line, for example. Ideally, a mechanical switch is used for this. However, if switching should occur via an electrical signal, an electronic switch is usually more suitable. Such an electronic switch can be built with a MOSFET as a  switching element. In addition to a purely discrete solution with a MOSFET, numerous semiconductor ICs are available for easy implementation of an electronic switch.