Switches are electrical devices that control the flow of current in a circuit. They are used in a wide variety of applications, from turning on and off lights to controlling complex electronic systems.

There are many different types of switches, but they all work in basically the same way. When a switch is open, the circuit is incomplete and no current can flow. When the switch is closed, the circuit is complete and current can flow.

Switches are typically classified by the number of positions they have and the number of terminals they have. For example, a single-pole, single-throw (SPST) switch has two terminals and two positions: on and off. A double-pole, double-throw (DPDT) switch has four terminals and four positions: on-on, on-off-on, and off-on-off.