| 摘要 |
PURPOSE:To decrease the amount of the leak current and then secure the assured resetting of the three-terminal switching element to OFF, by amplifying the trigger transistor with the output of the near-by sensor circuit to give the control to the three-terminal switching element. CONSTITUTION:The AC power source 25 is connected in series to load 26 via wires 22 and 23, and three-terminal switching element 21 is connected to these two wires via rectifying circuit 24. Then near-by sensor circuit 11 is connected between the anode and the cathode of element 21 via current limiting resistance 44, and output transistor TR13 is turned on and off by the output of circuit 11. Here trigger TR31 is controlled by TR13 to perform the amplifying action, and thus the gate trigger current is supplied to element 21. And diode circuit 42 supplies the power to circuit 11 when element 21 is on. As a result, the amount of the leak current required by circuit 11 for sensing action can be decrease when element 21 is off, and at the same time element 21 can be reset of OFF in the assured way. |
