What is a three-way switch used for?

A three-way switch is designed specifically to control a single light fixture from two different locations, making it particularly useful in hallways, large rooms, or staircases where you might want to turn the light on or off conveniently from either end.

In a typical setup, two three-way switches are installed, allowing for a circuit that enables the user to toggle the light on and off from either switch location. This enhances the functionality and convenience of lighting in various spaces, improving user experience and safety.

The other options do not accurately describe the primary function of a three-way switch. Controlling multiple light fixtures typically involves different wiring configurations, such as using a four-way switch for additional control points. Connecting two circuits together is not a function of a three-way switch; such tasks require different types of switches or junction connections. Lastly, increasing the voltage in a circuit typically pertains to transformers or specific voltage regulators, not to the operation of a switch.