TORQUE SENSOR

PURPOSE:To obtain the output voltage corresponding to torque and to detect torque without receiving the effect of the circumferential temp. by differentially amplifying the output voltage of a DC voltage detection circuit and the output voltage of an AC voltage output detection circuit and setting off the voltage change component corresponding to the circumferential temp. CONSTITUTION:The AC voltage being the oscillation voltage including DC voltage of an oscillation circuit 10 oscillating high frequency is applied across both terminals of a series circuit of a voltage dividing resistor 11 and a torque detection coil 12. The AC voltage including DC voltage of the torque detection coil 12 is applied to a low-pass filter 13 and a clamp circuit 15. The output voltage of the low-pass filter 13 is inputted to an amplifying circuit 14 and the output voltage of the clamp circuit 15 is inputted to a peak detection circuit 16. The DC voltage corresponding to the circumferential temp. is obtained from the amplifying circuit 14 and the AC voltage corresponding to the circumferential temp. and torque is obtained from the peak detection circuit 16. The DC voltage of the amplifying circuit 14 and the DC voltage of the peak detection circuit 16 are differentially amplified by a differential amplifying circuit 17 and the voltage change corresponding to the circumferential temp. is set off to perform the compensation of temp. and only the output voltage corresponding to torque is obtained from the circuit 17 and torque not receiving the effect of the circumferential temp. can be detected.