| 摘要 |
A circuit for switching a voltage between a pair of terminals by means of a thyristor, preferably a silicon controlled rectifier (SCR), connected at its anode to one of the terminals and at its cathode to the other terminal, is characterized by a control switch connected with a normally open contact thereof between the gate and the anode of the SCR, and with a normally closed contact controlling the voltage at the gate of the SCR. With the control switch in its normal or "off" condition, the SCR is nonconductive and the voltage at the gate thereof is controlled independently to adjust the voltage at which the SCR would be turned on by a rapidly increasing voltage between the terminals, i.e., to adjust its dv/dt withstand capability. With the switch in its "on" condition, the gate is disconnected from control voltage and connected to the anode of the SCR, thereby to minimize the gate current required to render the SCR conductive.
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