| 摘要 |
PURPOSE:To realize the prevention of power from being left not turned off and the function as a sleep timer, by constituting a titled circuit that the power supply is turned off after a prescribed time after a set is not in operation. CONSTITUTION:A sound signal inputted from a sound signal input terminal is rectified at a rectifier circuit and inputted to a base of a transistor (TR) 8. The TR8 is turned on with its input, a terminal 30 of a PUT7 goes to ground potential, a timer circuit using the PUT7 is inoperative and a TR10 is turned off and a TR11 turns on. Thus, a relay 6 is operated to turn on a contact 5 and set is operative. When the sound signal is lost, the TR8 is turned off. Then, a capacitor 17 is started for charging via a resistor 24, and at the moment when the potential exceeds a potential at a terminal 29 of the PUT7, the PUT7 turns on. When the PUT7 turns on, the TR10 turns on, and the TR11 is turned off, the relay 6 is restored, the contact 5 is opened and the circuit of the set is released from the power supply. |
