| 摘要 |
PURPOSE:To stop a leak current by driving a transformer with a means which takes out a square wave and generating power insulated from the power of a synchronizing signal generator in the secondary side of the transformer. CONSTITUTION:The output of a square wave shaping circuit 3 is inputted to the primary side of a transformer 4 whose passing band is a frequency higher than the horizontal synchronizing frequency, and insulated power is generated in the secondary side and is supplied to a rectifying circuit 5. The power converted to a DC by the circuit 5 is supplied to an amplifier 6 of a microphone or the like. The signal from a microphone input 7 is amplified by the amplifier 6 and passes an audio coupler 8 and is outputted to an audio output 9 and an output earth 10. At this time, the secondary side of the transformer 4, the circuit 5, the amplifier 6, the coupler 8, and a microphone earth 11 constitute a small-sized power earth 12, and the earth level is a common earth and is insulated from a power earth 13 of a power source 1. |
