| 摘要 |
PURPOSE:To simplify the constitution of a circuit, by detecting an increase in the voltage between a collector and emitter when an overcurrent is given to a TR and interrupting the base current. CONSTITUTION:A base current is applied to a TR1 from a controller 5 at a normal state, to turn on th TR. If an overcurrent due to any cause flows to the TR1, the voltage between the collector and emitter of the TR1 is increased. This voltage is detected at a voltage detector 2, a switch driver 3 is operated to turn on a switch 4. Then, a current flowing to the base of the TR1 from the controller 5 flows to the switch 4, no current flows to the TR1 and the TR is turned off. The voltage detector 2 and the switch driving circuit 3 can be formed with a simple circuit and the switch 4 can be formed with TRs and thyristors. |
