| 摘要 |
PURPOSE:To simplify the constitution of an overcurrent protective circuit and to increase its economical efficiency by a method wherein the secondary winding of the exciting transformer and the series circuit of an overcurrent detecting resistor are inserted in between the base emitters of a switching transistor. CONSTITUTION:The overcurrent detecting resistor 23 is connected between the emitter of the switching transistor Tr10 and one end of the secondary winding of the exciting transistor 12. Also, a diode 24 is connected between a starting circuit 5 and an output voltage terminal 20. When an overcurrent is running to a nonstabilized DC current terminal 1, the Tr10, the resistor 23, a chock coil 16 and a terminal 20 due to the generation of short-circuit and the like between the output terminal 20 and an earth 4, the Tr10 is turned to an inverted bias state by the help of the current running to the secondary winding of the transformer 1 connected to the resistor 23, and the Tr10 is cut off. The diode 24 prevents the reoperation of the starting circuit 5 after the Tr10 has beeen cut off. |
