Abstract: An improved switch for power factor correction circuits includes a six-terminal switch which has a first inductor connecting to a selection line which has a first switch terminal and a second switch terminal, and a second inductor connecting to a conductive line. When the switch is at a first position, the selection line is connected to the first switch terminal, and the conductive line is closed to determine the first and second inductors in a parallel coupling condition and the power conversion circuit in a first duty condition. When the switch is at a second position, the selection line is connected to the second switch terminal and the conductive line is open to determine the first and second inductors in a serial coupling condition, and the power conversion circuit in a second duty condition.

Abstract: The present invention discloses an improved passive power filter circuit, wherein a rated compensating voltage is provided for the power factor compensating circuit in order to solve the problem of instable power output resulting from that the rated voltage is obtained via bypassing the standby power supply circuit in the conventional technology. Further, in the present invention, a circuit is used to pre-charge two filter capacitors, which are coupled to the DC output terminals of a rectifier, in order to offset the current phase advance or the current phase lag, which the conventional passive power filter circuit cannot solve, and thereby, the power factor is improved.