| 摘要 |
PURPOSE:To facilitate the formation of an IC and at the same time to save the power consumption for a titled amplifying circuit, by using the transistors and resistors with a reduced number of capacitors. CONSTITUTION:When the DC voltage is applied to a terminal 49, transistors TR50-54 are turned on to actuate TRs 3, 5 and 6. Then the power is supplied to a radio receiving circuit 45 from a terminal 55 of the emitter side of the TR54, and the output wave detection signal given from the circuit 45 is amplified and transmitted through a speaker 25. When the DC voltage is cut to the terminal 49, no output voltage is delivered from the terminal 55 to cut the supply to the circuit 45. At the same time, no current flows to the TRs 3, 5 and 6. An alarm sound can be transmitted through the speaker 25 by applying the prescribed signal to a terminal 56 although the radio is not active. |
