| 摘要 |
PURPOSE:To provide adjustability for the output power to a low value by furnishing a means to control the value of input current amount given by AC power supply, and thereby controlling the voltage at the ends of an equalizing capacitor under the power supply voltage. CONSTITUTION:An input setting circuit 31 sets the value of input current IIN from commercial mains 1 to a certain value, and the set information is passed to an input control circuit 33. This input control circuit 33 gives a pulse signal 33a to the base of a transistor Tr1 so that the set input current IIN is attained on the basis of the set information from the input setting circuit 31. A load sensing circuit 35 sends a gate signal to thyristors 7a, 7b of a bridge circuit 5 to control the continuity angle of them 7a, 7b, and the value of input current IIN from the commercial mains 1 is adjusted. According to this constitution the voltage Vdc at the ends of an equalizing capacitor 11 can be adjusted, lower than the power supply voltage of commercial mains 1, and the output power is adjustable any desired from a low value to the max. value. |
