Demystifying TRIACs: Understanding How They Work and Testing for Optimal Performance

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. In today’s topic we will learn what is triac in electronics , how does it works , and what applications it is used in.
TRIAC stands for TRIode for Alternating Current, is a type of semiconductor device used in electronic circuits for controlling the flow of electric current, specifically in alternating current (AC) applications. TRIACs are members of the thyristor family and it can conduct current in both directions, allowing them to control AC power by regulating the flow of current during both positive and negative halves of the AC waveform.
A TRIAC has two diode and three terminals: MT1 (Main Terminal 1), MT2 (Main Terminal 2), and gate terminal.
Lets understand how does traic actually works,
TRIAC is triggered into conduction by applying a voltage or current pulse to its gate terminal. Shown circuit is built to control a light bulb using triac , where the control voltage applied at gate terminal are 1.5 volt and Mt1 and MT2 terminal connects the bulb to the power supply at 15 volt. Once the switch is turned on 1.5 voltage are applied to gate terminal and triac starts to conduct current between mt1 and mt2 terminal and bulb lights up.
Now we know how triac works, lets learn how to test if the triac is good or faulty using multimeter.
Step 1,
Set the multimeter on diode mode as shown and put the black prob on gate terminal and red probe on MT1 terminal it should show reading around 60 to 80, even when the probes are inverse it still should show the same reading.
Step 2,
Now keep the black probe on gate terminal and put red probe to MT2 terminal it should not show any reading.
Step 3,
Put the red probe on MT1 and black probe on MT2 terminal It should not show any reading. This indicates it’s a good Triac.
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