Abstract: A pulsating circuit suppling a pulsating voltage to a load when a capacitor is not discharged, and a control circuit which controls discharging the capacitor. The control circuit includes a smoothing circuit, and a voltage detection circuit. The voltage detection circuit includes a first switch that is turned off by detecting the pulsating voltage is in a voltage range; a second switch connected to the first switch and is turned on when the first switch is turned off; and a third switch connected to the second switch and is turned on when the second switch is turned on When the pulsating voltage is not in the discharge voltage range of the capacitor, the first switch is turned on and the second and third switches are turned off. A discharge voltage of the capacitor is set within a range that is slightly higher than a lower limit of a voltage.