PURPOSE: To reduce loss and miniaturize a rectifier circuit, by employing a MOSFET in the rectifier circuit.

CONSTITUTION: A rectifier circuit consists of an AC power source AC, a power source transformer T, MOSFETs 1∼3, resistors R1, R2, a capacitor C and the like and supplies electric power to a DC load RL. The capacitor C is charged when the polarity of the AC power source AC is in a direction to impress a positive voltage on the drain electrode of the MOSFET 1 and the capacitor C is charged in the same manner when the polarity is reverse. The MOSFET 2 is put ON through a resistor R2 when the positive voltage is impressed on the drain of the MOSFET 1 while the MOSFET 1 is also put ON, whereby charging is effected through a low resistance in the FET 1. The charging under the reverse polarity is effected through the low resistance in the MOSFET 3 in the same manner. According to this constitution, a loss due to voltage drop may be reduced and generation of heat resulting from the voltage drop may be reduced.