| 摘要 |
PROBLEM TO BE SOLVED: To provide a safe and inexpensive torque detector having temperature compensating function and failure detecting function by a pair of coils of one series. SOLUTION: A pair of coils 17 and 18 is serially connected to a load resistor RL, an AC driving voltage V1 is applied to the serial circuit. A differential amplifier circuit 31 outputs a differential voltage V3 between the voltage value V1 of the serial circuit and the voltage value V2 of the connection point of the coils, a first synchronous wave detecting circuit 107 performs a wave detection synchronously to the driving voltage V1, and a torque output circuit 23 outputs a torque signal based on the difference or ratio of impedance of the coils. A second synchronous wave detecting circuit 108 performs a wave detection synchronously to a control signal having a phase different from the driving voltage V1 by 90 deg., and a failure detecting circuit 109 performs a failure judgment on the basis of the sum of the impedances of the coils.
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