PURPOSE: To minimize variations in a threshold, by detecting current flowing through a resistance connected between a resistance connected to a negative power source and the ground with a switching comprising a resistance and a transistor to set a threshold value of a detection current by a resistance value.
CONSTITUTION: The title circuit combines a negative power source 1, a resistance 2 and the ground 6 to detect current flowing through a resistance 3 with a detection circuit comprising transistors 8 and 13, resistors 5, 7, 10 and 11, diodes 4 and 14, a positive power source 9 and the ground 15. A threshold of a detection current is set by resistance values of the resistances 5 and 10. Then, as the detection current exceeding the threshold flows, a base potential of the transistor 13 increases to turn ON the transistor 13 and a detection signal is outputted to an output terminal 12 thereby minimizing variations in the threshold.
FUJISHIRO SHIGEKI
TAGATA TSUGINORI
MIYAGI NIPPON DENKI KK
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