| 摘要 |
PURPOSE:To constitute a strain gauge of a type to be stuck to the surface of an object, so that it is not influenced essentially by a temperature variation, by measuring a phase difference of a high frequency voltage, as a physical quantity corresponding to a strain. CONSTITUTION:Electrodes 3 of four pieces each are arranged in two parts of the surface of an insulating substrate 2, and a high frequency voltage whose phase has been shifted by 90 deg. each to each adjacent electrode is impressed to these electrodes. Also, an electrode 5 is provided on two parts, too, of the surface of an insulating substrate 4, and joined at a part of a spacer 17 so as to be opposed to the electrode 3. The substrate 2 is stuck to an object to be measured 1, and expands and contracts by following its expansion and contraction. According to this constitution, when a voltage is impressed to the electrode 3, a voltage of the same frequency is induced in the electrode 5 and an output electrode 13. A phase of the voltage of the electrode 13 becomes a function of a relative position of the electrodes 3, 5, but a phase decomposition can be executed comparatively easily. The expansion and contraction caused by a load, etc. of the object to be measured 1 generates a relative displacement which is equal to the expansion and contraction of the object to be measured 1 between the electrodes 3, 5, but as for a temperature variation, the relative displacement is not generated by using the substrates 2, 4 which is very small, and whose coefficient of thermal expansion is nearlyh equal to that of the object to be measured 1.
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