| 摘要 |
PURPOSE:To obtain an input circuit with convenience in usage by obtaining always an output signal of the same polarity even if the change in the polarity of a voltage signal output of an input circuit group is conversed. CONSTITUTION:Plural input circuits are provided respectively and a group comprising plural gate circuits 11-1, 11-8 turning on/off outputs of voltage level detection circuits 10-1, 10-2 is provided to a group different from the connection method of contacts in a conversion circuit 1. Then a gate circuit of one group is turned on selectively, and voltage level detection circuits 12-1, 12-2 detecting a voltage level of the 2nd terminal connected in common in each input circuit group are provided and its output is inputted selectively one terminal of exclu sive OR circuits 15-1/-15-4 via a multiplexer 13. A high level or a low level voltage output is obtained in response to the on/off of a contact 2 by detecting the dissidence of both inputs from the circuits 15-1-15-4.
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