POSITION DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a position detecting device which has a simple structure and is small-sized and low-cost. SOLUTION: The position of a linearly displaced member 13 which is nearly displaced as a ball screw 12 driven by a motor 11 to rotate is detected. A detected body substrate 16 is fixed to a support member 17 opposite to a magnetic sensor 15 installed on the linearly displaced member 13. A desirable conductor selected out of conductor patterns P1, P2... of the detected body substrate 16 is applied with an AC signal from an AC signal generating circuit 19 to produce an AC magnetic field around it and a magnetic sensor 15 detects the AC magnetic field. A discriminating circuit 21 is supplied with an AC signal which has the same waveform and phase with the AC signal applied from the AC signal generating circuit 19 to the conductor patterns P1, P2... together with the detection signal of the magnetic sensor 15.