| 摘要 |
PURPOSE:To attain the quick operation by providing a switching transistor (TR) respectively among the base, emitter and ground terminal of a rectifier TR, turning on the switching TR at application and interruption of power so as to inhibit the charging to a rectifier capacitor thereby discharging the electric charge. CONSTITUTION:A collector/emitter of a TR 34 is connected between a base of a TR 14 of emitter follower and ground and the base of the TR 34 is connected to a power supply application/interruption detection circuit 40 via a resistor 36. The collector of the TR 34 is connected to the base of the TR 14, the emitter is connected to ground and the base is connected to ground via a resistor 35. A TR 37 is provided between the emitter and ground of the TR 14 and the base is connected to the circuit 40 via a resistor 33 and connected to ground via a resistor 38. The output of the circuit 40 is at L except at a short time at power application/interruption, the TRs 34, 37 are turned off, the AGC is operated normally, the output is at H at the application of interruption of power, the TRs 34, 37 are turned on simultaneously, the TR 14 is turned off to interrupt the supply of electric charge to a capacitor 19, the stored electric charge is discharged via the TR 37 and the titled circuit follows sufficiently the quick repetitive operation.
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