| 摘要 |
PURPOSE: To obtain a device for measuring the variation of capacitance between a diaphragm and fixed electrodes facing the central part and outer circumferential part thereof, respectively, in which the accuracy of measurement is enhanced by supporting a fixed electrode supporting plate through a rolling bearing thereby preventing deformation of the electrode due to temperature fluctuation. CONSTITUTION: A fixed electrode 340 is arranged in the center on the surface 310 of a supporting plate 300 facing a diaphragm and a fixed electrode 342 is arranged on the outer circumference thereof. A rolling bearing 370A made of an electric insulating material, e.g. sapphire, is provided on the supporting shoulder 330 of supporting plate 300 supported by a supporting shoulder structure 150. This structure prevents deformation of the electrode 342 due to temperature fluctuation and suppresses temperature fluctuation of the capacitance between the diaphragm and electrodes 340, 342, thus ensuring accurate measurement. |
