| 摘要 |
PURPOSE:To make the protection of the power amplifier and its effective use, by turning on and off the power supply to the power amplifier by means of the output of the power amplifier. CONSTITUTION:In a component type stereo reproducing unit, the power supply circuit 6 performs power supply to the power amplifier 2 accompanied with the power switch 2 ON. On the other hand, when the output of the amplifier 2 is integrated and it reaches a given value, the time constant circuit 7 turns on the transistor TR8 of the circuit 6 and TR8 compulsively turns off TR61 of the circuit 6. Thus, the driving of the relay 62 is OFF and the contact 63 is OFF. Accordingly, since the output of the amplifier 2 turns on or off the power supply 4 applied to the amplifier, the power amplifier can be protected and the limit of the input applied with the ON or OFF of the amplifier 2 can be known, allowing to use the power amplifier efficiently. |
