| 摘要 |
A switch-arc preventing continuous current circuit for protecting pulsing contact telephone exchange switches, the circuit having a first transistor in circuit with and controlled by a control transistor, the power electrodes of the first transistor being disposed in circuit between an inductive coil of a stepping solenoid and a protected switch, a bias voltage source connected to a terminal of the protected switch by a blocking diode and a pair of resistors in series, and a metal oxide varistor in shunt across the power electrodes of the first transistor.
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