3-Way Light Switches Working Principle Animation

We use light switches every day, and yet have you ever seen the inside of one? In this video we open up 3 types of light switches: the basic light switch, 3-Way light switches, and 4-Way light switches. We also explore how they can be wired together to turn on one or multiple lights.How do 3-Way Light Switches Work? Also, let’s look at 4-Way Switches, and Basic Light Switches! 

A 3-way switch has three terminals, one common (usually black colored) and a pair of travelers (usually brass colored). With traditional wiring, the common wire from one switch connects to the line, the common wire from the other switch connects to the line. Load (light). A pair of travelers on one switch connects to a pair of travelers on another switch.

The switches must form a complete circuit for current to flow and the bulb to light. When both switches are up, the circuit is complete (top right). When both switches are closed, the circuit is complete (bottom right). If one switch is up and one is down, the current stops, no current flows and the bulb is off (top left and bottom left). These switches appear externally similar to single pole, single throw (SPST) switches, but have additional connections that allow a circuit to be controlled from multiple locations.