Triacs are three-terminal semiconductor devices used for controlling current. Their bidirectional construction means that current can flow through them in either direction. An acronym for Triode Alternating Current, Triacs are commonly used with AC switching applications. Common examples include small motor controls, dimmer switches and the speed controls on an electric fan.
The three terminals of a triode are commonly described as Terminal 1, Terminal 2 and the gate; T1 and T2 serve as the major current-carrying terminals, while the gate serves as a trigger.
Owners can test the health of a triac by following a few quick steps: