POWER SUPPLY

摘要

PROBLEM TO BE SOLVED: To obtain a power supply employing a plurality of capacitors in the power supply source wherein power factor is enhanced by suppressing input current harmonics. SOLUTION: A variable resistor 5 is connected in parallel with the output terminal of a full-wave rectifier 2 for rectifying commercial AC input and a plurality of series circuits of variable resistors 6-1 to 6-n and capacitors 7-1 to 7-n are connected in parallel. Impedance of each variable resistor is controlled variably through an impedance control circuit 8, 9-1 to 9-n wherein the variable resistors 6-1 to 6-n are controlled to have a finite impedance only during a period for charging the corresponding capacitors and have an infinite impedance during other period.