In a thyristor

In a thyristor

Right Answer is:

The latching current is greater than the holding current


Latching Current (IL)

The latching current is the minimum value of anode current to trigger or turn ON the thyristor from its OFF state to ON state even after the trigger pulse is removed. To trigger an SCR, the anode current must be build-up to the latching current before the gate pulse is removed.

Holding Current (IH)

The holding current is the minimum value of the anode current to hold the thyristor in the ON state. During turn OFF, the anode current should be below the holding current.  Usually, the value of holding current is in milli-ampere.

If holding current was equal to the latching current, small flickers in the signal would cause the SCR to oscillate between turn-ON and turn-OFF, which is undesirable. So the latching current limit is usually greater than the holding current so as to avoid the misfiring of SCR and provide trouble-free operation.

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