Triac

For people who check facts

A triac is an electronic component where 2 silicon controlled rectifiers are joined end to end or back to back while their gates are connected together. This results in a two directional "diode" electric switch where the current can flow in both directions when it is triggered (turned on). The device turns off again when the current through it drops below a certain threshold value. This makes the triac a convenient switch for AC circuits. Lower power ones are used everywhere, especially appliances.