| 摘要 |
PURPOSE:To obtain the humidity sensor which prevent an accident such as burning due to current flow by providing invariably a humidity sbsorbing member on an earth electrode. CONSTITUTION:An electric signal from an AC signal generator is applied to electrodes 2, 2', and 2' through lead lines 4' and 4', and then piezoelectric elements 1 and 1 move as shown by an arrow at some moment and move in the opposite direction at the next moment to generate flexural oscillation. Then, a driving frequency is adjusted to the resonance frequency of the flexural oscillation to perform efficient operation. Further, the amount of water sticking on both humidity absorbing members 3 and 3' varies with ambient humidity and the members 3 and 3' vary in mass to cause variation in resonance frequency, thereby obtaining variance in impedance or admittance with the resonance frequency. Namely, the humidity sensor detects variation in humidity in the air in the form of variation in resonance frequency of variation in impedance or admittance with resonance frequency. |
