How does a three-way switch function in a lighting circuit to control a single light fixture from two different locations?

A three-way switch in a lighting circuit allows you to control a single light fixture from two different locations. The switch has three terminals that are connected to the power source and the light fixture. By flipping the switch up or down at either location, you can turn the light on or off. The switches work together to alternate the flow of electricity, allowing you to control the light from multiple spots.