| 摘要 |
PROBLEM TO BE SOLVED: To provide an input circuit with general applicability in which the number of constituting elements is reduced and an energy loss is cut down. SOLUTION: This input circuit is provided with a constant current source U4 connected with a power source, input terminals S5 and S6, a pair of PNP transistors Tr10 and Tr11 whose bases are connected with the input terminals S5 and S6 respectively, whose emitters are commonly connected with a constant current source U4 and of which collectors are grounded, a resistance R7 interposed between the collector of the transistor Tr11 and ground, and an output terminal T5 connected with a node part N3 between the collector of the transistor Tr11 and the resistance R7. In this case, when the voltage value of a reference signal to be applied to the input terminal S6 reaches a threshold value and an input signal inputted to the input terminal S5 is beyond the threshold value, it is judged that an on signal is inputted, and a signal for indicating the judged result is outputted from the output terminal T5.
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