Latching Current of a Thyristor

Latching Current

Latching current is defined as the minimum value of the anode current required during turn on process of a thyristor to remain in conduction even after the gate signal is removed.

After the thyristor is turned on and is conducting in forward conduction mode the reverse biased

junction J₂ no longer exist. Under this condition the gate signal is no longer required to maintain the thyristor in on state. But if the gate current is removed before the anode current reaches a certain value called latching current, the thyristor will turn off again. Hence, to fully turn on a thyristor the gate signal should only be removed only after the thyristor anode current attains the latching current.