{i} semiconductor device used as a switching device for alternating currents (Electronics)
A three-terminal silicon device that functions as two SCRs configured in an inverse, parallel arrangement, providing a means of providing load current during both halves of the AC supply voltage A TRIAC is generally used for motor speed control Since load current (armature current) flows during both halves of the applied AC voltage, the motor rotates smoothly at all rotational speeds
Similar to a thyristor but allows current to flow in both directions as in diagram below