| 摘要 |
PROBLEM TO BE SOLVED: To improve the detection accuracy of a sensor by adding the output voltage having a positive temperature characteristic from a temperature correcting means and the output voltage having a nagative temperature characteristic from a rectifying means with an adding means, and offsetting the temperature characteristics. SOLUTION: A constant current with the prescribed frequency is fed to the exciting coil 5a of a sensor 1 from an AC exciting power source 19 through an exciting amplifier 17. When compressive stress is applied to a magnetostrictive element 3, the magnetic flux crossing a detecting coil 5b vertically crossing the coil 5a is generated on the element 3, the voltage proportional to the stress is generated on the coil 5b and rectified by a rectifying circuit 21, and the voltage VIN having a negative temperature characteristic is outputted. A constant DC voltage is fed to a diode 33 from a constant DC voltage source 29. The output voltage V1 of the cathode terminal of the diode 33 has a positive temperature characteristic. The voltage VIN and the voltage V1 are added at a connecting point 24 and inputted to a voltmeter 39 via an arithmetic amplifier 25. The voltage faithfully indicates the stress applied to the sensor 1, and the stress can be known from the indicated value. |
