| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power circuit which can reduce power consumption and where output voltage is stable even in the case that there is ripples in power voltage. <P>SOLUTION: A voltage drop circuit, which consists of a diode bridge 10, a three-terminal regulator 11, and a resistor 2, is connected in series to the primary winding 3a of a power transformer 3. Moreover, this power circuit is provided with a switch 5 which short-circuits the above voltage drop circuit on standby of an electric apparatus. By such constitution, the standby power can be reduced since the voltage between both ends of the primary winding 3a of a power transformer on standby becomes smaller than that in an operation state, and the voltage to be outputted to a control circuit 2 becomes stable since the AC current flowing in the primary winding 3a of the power transformer becomes constant on standby. <P>COPYRIGHT: (C)2004,JPO |
