Definition of triac in English:


Pronunciation /ˈtrīak/ /ˈtraɪæk/


  • A three-electrode semiconductor device that will conduct in either direction when triggered by a positive or negative signal at the gate electrode.

    ‘The microcontroller assures control of switch means, such as triacs, switches and relays, and ensures that braking is effectuated regardless of the phase in the power cycle of the alternating current.’
    • ‘A second triac or the like is connected between the intermediate point of the winding and the terminal of the voltage supply to which the first triac is connected.’
    • ‘A lamp module is similar, but has a triac instead of a relay and will respond to dimming commands as well as on or off commands.’
    • ‘Triacs come in many shapes, sizes, and colors.’
    • ‘A triac is an AC conduction device and may be thought of as two antiparallel thyristors monolithically integrated onto the same silicon chip.’


1960s from triode+ AC (short for alternating current).