What is a 3-way switch used for?

A 3-way switch is primarily designed to control lighting from two different locations. This setup is commonly used in situations where you want to be able to turn a light on or off from two separate points, such as at the top and bottom of a staircase or at either end of a long hallway. By utilizing two 3-way switches, the circuit allows for flexibility and convenience, enabling users to control lighting without having to return to the original switch location.

The other options do not accurately describe the function of a 3-way switch. For example, controlling multiple devices from one location typically involves the use of a standard switch or multiple switches in a circuit, rather than a 3-way configuration. Enhancing voltage output is more associated with boosting transformers or other devices, not with the operation of switches. Bypassing circuits may refer to different electrical configurations and safety practices, but does not pertain to the intended use of a 3-way switch in a lighting arrangement.