TWO-WAY THREE-TERMINAL THYRISTOR SWITCH CIRCUIT

摘要

PURPOSE:To miniaturize a gate circuit by connecting a diode in an opposite direction to a capacitor for storing electric charge flowing a gate current of a thyristor switch circuit so as to reduce the capacitance of the capacitor of the circuit and the capacity of a DC power supply. CONSTITUTION:A two-way three-terminal thyristor switch circuit 14 is provided with a two-way three-terminal thyristor (SCR) 3 and a gate circuit 10 connected to an electrode T-1 of the SCR3 and a load 2 and an AC power supply 1 are connected in series between electrodes T-2 and T-1 of the SCR3. A DC voltage 9 is connected to a transistor TR8 inputting 1 control signal of the circuit 10 via a resistor 7. Further, a series circuit comprising a diode 3 and the capacitor 6 for storing electric charge is connected between the electrode T-1 of the SCR3 and a collector of the TR8. A diode 13 is provided to the capacitor 6, the connection is made in forward direction to the power supply 9 and in opposite direction to the stored electric charge of the capacitor 6. Then the capacity of the power supply 9 and the capacitance of the capacitor 6 are reduced so as to miniaturize the circuit 10.