| 摘要 |
PURPOSE:To enable to control an output voltage by the circuit itself by a method wherein at the first step or at a lower order step of plural steps rectifying circuit being connected in series, a circuit part to control the output voltage of that step is provided. CONSTITUTION:Outputs of the plural steps rectifying circuit are connected in series, and at the first step or at the lower order step, the circuit part to control the DC output voltage of that circuit is proided. For example, a voltage control part consisted of Zener diodes (ZD) D6, D7 and an NPN transistor (Tr) Q1, etc., connected in series is provided at the first step to constitute the circuit as shown in the figure. The voltage V1 to be generated between the both ends of the secondary winding of a transformer T and the Zener voltage VZ of the respective ZD's are made to hold the relation 2V1>2VZ>V1 enabling to obtain the DC output voltage 4V2 between the output terminals 1, 2 being controlled by the ZD's D6, D7. At this case, the DC output voltage can be regulated freely in the range up to the maximum voltage 4V1 by selecting the ZD. |
