| 摘要 |
PURPOSE:To reduce the variation of the output by turning ON a switching transistor by the transistor for switching at the atarting time, and separating the transistor after starting and turning the transistor OFF. CONSTITUTION:When a voltage is generated at the secondary side of a power source circuit, a control circuit CONT, to which a voltage is supplied from the secondary side, is operated. The circuit CONT varies the duty of the pulse to control so that the output voltage becomes ordinary state, a capacitor C2 is charged through diodes X2, X3 by the third secondary windings n2-3, thereby generating a voltage between the both terminals. Since this voltage reversely biases the base and the emitter of a switching transistor TR2, the switching transistor TR2 is turned OFF. Thus, resistors R1, R2 are isolated from the circuit, and the variation of the output voltage becomes small. |
