Plus and minus reversal supply of electricity state distinction device

摘要

PROBLEM TO BE SOLVED: To enable supply of DC power to a load in a terminal from a power supply part of a control unit from both positive and negative directions, thereby discriminating the state of a state switch easily. ;SOLUTION: A control unit AQ1 is equipped with a signal generating part 1a, a transformer drive circuit 2, a current-voltage conversion circuit 3, an envelope detecting circuit 4, an A/D conversion circuit 5, and a signal selecting part 1b. The transformer drive circuit and a state switch are connected to primary coils 12a and 13a of a balance transformer 12 at a control unit and a balance transformer 13 at a terminal respectively, and a closed loop is formed by secondary coils 12b and 13b of both balance transformers 12 and 13, capacitors C3 and C4 at both control unit and terminal and two lines connecting the control unit and a terminal, while a load and a power supply part are connected in parallel to both capacitors C4 and C3 respectively.;COPYRIGHT: (C)1998,JPO