| 摘要 |
PURPOSE:To obtain a moisture sensor with a wide voltage application range without deterioration regardless of erroneous long-term application of DC voltage, by arranging a pair of planar bodies each comprising a porous ceramic base body and an electrode plate inserted securely into a hollow part thereof to make surfaces thereof as opposed to each other and a gap is provided between the opposed surfaces to communicate with outside air. CONSTITUTION:An electrode plate 3 inserted into a hollow part 1 of a circular porous ceramic base body 2 is fastened on the base body 2 to form a planar body 4. Then, for example, an insulation support 5 is bonded at four points in the perimeter of the electrode plate 3. Moreover, an electrode plate 7 of a planar body 8 of the same structure as that of the planar body 4 is placed on the other end face of the insulation support 5 to stick together and a gap 9 is provided between the planar body 4 and the planar body 8 to communicate with outside air. This enables the production of a moisture sensor with a large electrostatic capacitance and a high sensitivity and free from deterioration or the like regardless of overvoltage or DC voltage applied.
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