| 摘要 |
PURPOSE:To prevent the mis-firing of the main thyristor due to the displacement current of the auxiliary thyristor, by inserting a capacitor between the main electrodes of the electric trigger main thyristor and the optical trigger auxiliary thyristor. CONSTITUTION:The series circuit of an optical trigger auxiliary thyristor 2 and a resistance 3 is provided between the gate electrode of the electric trigger main thyristor 1 having the breakover voltage of 2,000V or more and the main electrode distant from this electrode, and connection is made so that the forward current of the thyristor 2 can be the trigger current of the thyristor 1. Between the main electrode cathode close to the gate of the thyristor 1 and the electrode cathode connected to the gate electrode of the thyristor 2, a capacitor 5 having the capacity 0.02muF or more per the junction area (cm<2>) of the thyristor 2 is connected. Thus, the misfiring of the thyristor 1 due to the displacement current of the thyristor 2 can be prevented. |
