| 摘要 |
PURPOSE:To eliminate the effect of external environments such as temp. characteristics by constituting the capacity detecting part of a capacity sensor of respectively independent two detecting parts, and providing an oscillator circuit which generates the output signal of a predetermined resonance frequency according to the capacity changes of the respective detecting parts. CONSTITUTION:A pair of detecting electrodes constituted of electrodes 1, 2 and electrodes 2, 3 are disposed in the mutually different positions of the detecting region of an object to be detected, and an oscillator 6 puts out the output signal of a predetermined resonance frequency when the capacities across the detecting terminals of both detecting electrodes are equal. This output is put out from an output circuit 10 via a rectifier 7, an amplifier 8, and a Schmitt circuit 9. By this operation, the state of the object to be detected is detected. Then, all the operating conditions of the detecting electrodes are always the same, and the influence by the change in the atmospheres of the respective parts is eliminated virtually completely. |
