A family of emitter controlled thyristors employ plurality of control schemes for turning the thyristor on and off. In an embodiment of the invention a family of thyristors are disclosed all of which comprise a pair of MOS transistors (10, 20), the first of which is connected in series with the thyristor (2) and a second which provides a negative feedback to the thyristor gate. A negative voltage applied to the gate of the first MOS transistor (10) causes the thyristor to turn on to conduct high currents. A zero to positive voltage applied to the first MOS gate causes the thyristor to turn off. The negative feedback insures that the thyristor only operates at its breakover boundaries of the latching condition with the NPN transistor portion of the thyristor operating in the active region. Under this condition, the anode voltage Va continues to increase without significant anode current increase.
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