Time switch

A time switch (also called a timer switch, or simply timer) is a device that operates an electricswitch controlled by a timer.

Intermatic introduced its first time switch in 1945, which was used for "electric signs, store window lighting, apartment hall lights, stokers, and oil and gas burners." A consumer version was added in 1952.

The switch may be connected to an electric circuit operating from mains power, including via a relay or contactor; or low voltage, including battery-operated equipment in vehicles. It may be built into power circuits (as with a central heating or water heater timer), plugged into a wall outlet with equipment plugged into the timer instead of directly into the power point; or built into equipment.

The mechanism may be mechanical (e.g., clockwork; rarely used nowadays), electromechanical (e.g., a slowly rotating geared motor that mechanically operates switches) or electronic, with semiconductor timing circuitry and switching devices and no moving parts.