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Thyristor Power Controllers Information Center

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How do Thyristors work?

In the case of back to back SCRs, these allow the full wave current to be conducted. The forward SCR conducts during the positive half of the cycle, the reverse SCR during the negative half.

Each SCR is turned on at the appropriate time by a trigger pulse applied to the gate (a third leg) and the device will remain ON until the instantaneous load current through it drops to zero.

The trigger pulses are generated by a drive circuit which times the pulse to ensure the thyristor unit output is a function of the input control signal and firing mode.