| 摘要 |
PURPOSE:To reduce the power capacity of a current opening/closing element and the size of a magnetic core, by coupling a current limiting means and a current cutting-off means in series with a current opening/closing means. CONSTITUTION:When a load coupled to terminals 12, 13, 33 is short-circuited, a current limiting means 7 is opened by current cutting-of maeans 40 to cut off a current flowing through a current opening means 5. One terminal of a resistor 24 is coupled to the emitter of a trnsistor 20. A Zener diode 23 is connected between the base of the transistor and the other terminal of the resistor 24. Another transistor 21 is connected to the base of the former transistor 20 through a resistor 26. A capacitor 25 is coupled to the transistor 21. The collector and emitter of another transistor 22 are connected across the base and emitter of the former transistor 21. The base of the transistor 21 is connected to the termianl 33. The base of the transistor 22 is connected to the terminals 13, 33 through resistors 35, 36. |
