| 摘要 |
PURPOSE:To reduce the value of an internal resistance of a current detecting circuit by detecting the voltage between both ends of a resistor inserted to the path of a control current. CONSTITUTION:A current flows from a load 2 toward a negative voltage source 16 through a resistor 13, and a voltage is generated between both ends of the resistor 13, and the base potential of a transistor TR 10 is made higher than that of a TR 9, and the TR 10 is turned on and the TR 9 is turned off. When the TR 10 is turned on, a cut-off potential is supplied to the base of a TR 6 to turn off the TR 6, and the earth passing a resistor 7 is outputted to a detection output terminal 8. If the load is cut off or the DC resistance value of the load is increased, TRs 9 and 10 are turned off together and the TR 6 is turned on, and a voltage approximating the voltage of a positive voltage source 3 is outputted to the detection output terminal 8.
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