To provide an AC/DC voltage separating circuit such that an AC voltage is not applied to the side of a DC load Zdc by making the DC load Zdc apparently higher in impedance than the AC voltage AC through emitter voltage feedback effect of a transistor Tr.
The AC voltage AC extracted by a capacitor C1 connected to a line 10 applied with an input voltage comprising the AC voltage AC and a DC voltage DC which are superposed on each other is applied to an AC load Zac. The transistor Tr has its collector connected to the line 10 and its emitter connected to the DC load Zdc, has a resistance R1 interposed between the collector and base, and also has its base grounded through a second capacitor C2, and the DC voltage DC extracted at the emitter is applied to the DC load Zdc. Through the emitter voltage feedback effect, the DC load Zdc has a value tens of k when viewed from the collector side, so the AC voltage AC is not attenuated by the DC load Zdc and the AC voltage AC is not applied to the DC load Zdc either.
SANPO TAKESHI
ONO MOTOHISA
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