| 摘要 |
PURPOSE:To improve the operational characteristic of a protection circuit by dividing the base resistance of an oscillation transistor of a self-oscillation circuit into plural, making a protection transistor operated by a voltage at a point of this division, and thereby controlling the transistor of a control circuit. CONSTITUTION:When an oscillation circuit is in the state of oscillation, a voltage at a point of connection of base resistances 8 and 9 is in the state that a DC bias determined by the value of the base resistance 9 is applied on a capaciter 5 for regeneration, while a protection transistor 11 is maintained in an OFF state. When a high-voltage output is short-circuited, the oscillation is damped, thereby the voltage of the capacitor 5 for regeneration rises, the protection transistor 11 is turned ON, and an output voltage of a control circuit 10 is lowered. When an oscillation transistor 3 starts DC operation, the protection transistor 11 operates so that the base current of the oscillation circuit is made constant. |
