Overview

Triacs are semiconductor devices designed to work specifically with Alternating Current (AC).

How Triacs Work with AC?

  • Bidirectional Conduction:
    Triacs can conduct current in both directions (unlike SCRs/thyristors, which are unidirectional). Which makes triacs ideal for AC, where the current reverses direction periodically.
  • Switching AC Loads:
    Triacs are commonly used in AC dimmers, motor speed controls, and AC power switching because they can turn on and off at different points in the AC waveform.
  • Triggering Mechanism:
    A small gate current can turn on the Triac, and it remains conducting until the AC current crosses zero (natural commutation).

Why Not DC?

In DC, the current doesn't cross zero — it stays constant.
Once a triac is turned on with DC, it won’t turn off by itself, because there’s no natural current zero-crossing. It would stay on until the power is cut off or external circuitry is used to force it off.

Summary

Triac is Suitable for AC switching.For DC applications, consider using SCRs or MOSFETs.

Product Line

For more information about triacs' product line, please visit Semiware's official website：

https://en.semiware.com/products/3q-triac

About Semiware

Semiware has a comprehensive product lineup of circuit protection device products. The company leverages its technology in the semiconductor field and application background in end products to serve customers in the electronics, automotive and industrial markets. For more information, please visit semiware official website: https://en.semiware.com/