| 摘要 |
PURPOSE:To automatically cope with the input voltage of 100V and the input voltage of 200V. CONSTITUTION:A bidirectional three-terminal thyristor 18 is provided between one AC input part C of a bridge rectification circuit 2 and the middle point D between two capacitors 4 and 6. Besides, a voltage detecting circuit 20 is provided, which turns off the bidirectional three-terminal thyristor 18 when the voltage Vc is larger than the reference voltage and turn it on when smaller by comparing the voltage Vc across the two capacitors 4 and 6 with the reference voltage being set to the value equivalent to the voltage between the upper limit in the voltage ripple range of the input voltage V1 of 100V and the lower limit in the voltage ripple range of the input voltage V1 of 200V. |
