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A very compact solution for switching loads on AC power lines

Not limited by electromechanical ageing contingencies, triacs have a very long lifespan within circuits fully respecting specification boundaries.


With a voltage range from 600 to 800 V and up to 1200 V for certain industrial devices, ST's portfolio covers medium-power AC loads with 1 to 50 A triacs. 

With a range of driveable AC loads from 120 to 500 V, the list of circuits benefiting from ST triacs includes dimmers, all types of AC mains on-off switches, home or office copy/printer appliances, as well as industrial motor starters or SSRs, gardening tools, automated irrigation systems and a wide variety of automation controllers for factories, buildings and homes:

  • The high-voltage triacs are dedicated to industrial and three-phase mains switching applications.
  • Designed to ensure high switching performance in circuits that need space optimization, our 8T triacs are ideal for applications with high EMI constraints while our 6H triacs and 8H triacs target applications with high thermal constraints
  • Our standard and snubberless™ triacs retain the exhaustive gate drive possibilities and packages covering all power mains on/off and phase angle switching needs.
  • Featuring overvoltage protection functions, our ACS™ AC switches include highly inductive load switching capabilities for home and irrigation appliances including solenoid actuators and pumps, while our ACST triacs are designed for higher loads in appliances or equipment plugged in 24/7.

Triacs belong to our STPOWER family.

Ease your transition to surface-mount Triacs with our extended D²PAK portfolio

ST further extends its D²PAK offer for Triacs, ideal for compact designs. With parts ranging from 8 to 30 A, this Triac D²PAK offer is particularly suited for home and factory automation, allowing innovative designs with isolated metal substrate (IMS) and direct-bonded copper boards.
Discover our High-temperature Triacs and Standard and Snubberless Triacs in D²PAK.

800 V T-series triacs outrun competition for load control

800 V T-series high-performance triacs are designed for AC loads in industrial control and home appliances, enabling innovative and safe AC load control. With immunity (dV/dt) up to twice as high and commutation capability (dI/dt)c up to 5 times as good as state-of-art Triacs, this high-performance 800 V T-series triacs enables circuits to be more robust to EMI and loads to be fully controlled, with no disturbances. Its low gate current down to 10 mA helps optimize the power supply and allows direct drive capability through a single resistance between the microcontroller and Triac. 800 V T-series triacs are housed in TO-220AB, TO-220FPAB and now in D2PAK.



eDesignSuite is a comprehensive set of easy-to-use design-aid utilities ready to help you streamline the system development process with a wide range of ST products.

Thermal-electrical Simulators for Components

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AC Switches Simulator

Select ratings and application waveforms
Get junction temperature and blocking voltage graphs
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Rectifier Diodes Simulator

Select ratings and application waveforms
Estimate power losses
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Provides power loss and temperature graphs
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Twister Sim

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Supports load-compatibility, wiring harness optimization, fault condition impact and diagnostic analysis
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TVS Simulator

Specify system ratings and surge waveform
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