What is the primary function of a three-way switch in lighting circuits?

A three-way switch is primarily designed to control a light fixture from two different locations. This functionality is particularly useful in large rooms or hallways where you may want to turn a light on or off from either end of the space. When wired correctly, a three-way switch allows for seamless control, enabling a user to operate the lighting without needing to return to a single switch location.

The physical setup involves two three-way switches linked to the same light fixture, facilitating multiple points of operation. This arrangement enhances convenience and promotes safety by allowing individuals to control lighting as they enter or exit a room, which can be especially beneficial in preventing falls or accidents in poorly lit areas.

The other options reflect different functions that do not align with the purpose of a three-way switch. Dimming lights typically requires a dimmer switch, converting AC to DC power involves power supply conversion for compatible devices, and isolating a circuit is usually managed by circuit breakers or disconnect switches for safety during maintenance or emergencies.