Triode thyristors

The triode thyristor has two basic and one controlling lead terminals (Fig.6.4). It is also necessary to accumulate excess charges in the n- and p-base to turn on the thyristor. If we connect lead terminal to one of the bases, we can control the thyristor operation using anode or cathode circuit. The voltage applied to the controlling lead terminal facilitates appearance of the avalanche action. The ON voltage decreases when the controlling current increases (Fig.6.5).

Fjg. 6.4. Structure of a triode thyristor

b

Fig.6.5. Triode thyristor: a -current-voltage characteristic; b – connection

diagram