OPTICAL TRIGGER THYRISTOR

PROBLEM TO BE SOLVED: To provide an optical trigger thyristor having normal optical trigger sensitivity, which does not malfunction easily. SOLUTION: The optical trigger thyristor 1 comprises : a thyristor 2 having a p-type gate 2c and a cathode 2d, which is shifted from switch off state to switch on state by light irradiation ; a resistor 3 and a bipolar transistor 4 which are connected electrically between the p-type gate 2c and the cathode 2d in parallel wherein a base and a collector of the bipolar transistor 4 are connected electrically and a resistor 5 and a photodiode (optical trigger element) 6 which are connected electrically between the base and an emitter of the bipolar transistor 4 in parallel. A phototransistor, a photothyristor or the like can be used instead of the photodiode 6 as the optical trigger element. COPYRIGHT: (C)2004,JPO