CIRCUIT ARRANGEMENT FOR CONTROLLING A THYRISTOR WITH LIGHT

摘要

A circuit arrangement for drive of a thyristor with light comprises a zero pause control which permits an ignition of a thyristor only in a proximity of a zero point of the thyristor voltage. The control contains an IGFET which transports away a base current of the phototransistor effecting ignition when the thyristor voltage exceeds a specific value. The gate terminal of the IGFET connects to an alternating voltage via a photodiode. The zero point control can only be activated when the photodiode is illuminated.