| 摘要 |
PURPOSE:To enhance the detection accuracy of a water level, by simple constitution such that the water level is detected using the change in oscillation voltage generated when a ceramic vibrator is contacted with water or hot water and not contacted therewith. CONSTITUTION:A ceramic vibrator 1 is driven by an oscillation circuit 3 and vibrates at its own inherent vibration frequency. When water is supplied in a container 2 and the water level thereof reaches the ceramic vibrator 1 attached to the side wall of the container 2, the mechanical load of the ceramic vibrator 1 increases and, therefore, oscillation voltage is reduced. This change in the oscillation voltage is detected by a voltage detection means 4 and the output voltage thereof is compared with reference voltage 7 by a comparing means 5 and an alarm device 6 is driven using the output signal of said comparing means 5. By this method, the water level in the container 2 can be detected. Further, since the ceramic vibrator 1 is directly contacted with water to detect the water level, the water level can be known with high accuracy.
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