| 摘要 |
PURPOSE:To intercept a voltage quickly upon service interruption by a method wherein the output voltage of an output power source line, to which a capacitor is connected in parallel, is detected that it is reduced than a predetermined value upon the service interruption to discharge the capacitor through a low resistor. CONSTITUTION:A capacitor 32 is charged by DC current, obtained by rectifying an AC input by a bridge diode 31 through a transformer 2, to supply power to a load not shown in a diagram. A discharging circuit 4 and a control circuit 5 are connected between a DC output line L and an earth. In the control circuit 5, a voltage in accordance with a Zener diode 52 and resistors 53, 54 is generated upon normal time, a transistor Tr 51 is put ON, a collector potential Vc becomes zero and the thyristor 42 of the discharging circuit is being put OFF. When the AC input is interrupted, the capacitor supplies power to the load, however, the voltage of the same is reduced in accordance with the elapse of time. When the voltage is reduced to a predetermined value, the Tr 51 is put OFF, the collector potential Vc is increased, the thyristor 42 is put ON and the capacitor 32 is discharged quickly through a load resistor 41 of a low resistance. According to this method, the supply of power to the load may be intercepted quickly. |
