| 摘要 |
PURPOSE:To perform accurate measurement, by applying high frequency voltage to a signal electrode and measuring the liquid level on the basis of the detection voltage of a detection electrode. CONSTITUTION:Only the AC component of the high frequency pulse from an oscillator 3 passes through a condenser 5 to be applied to a signal electrode 1 and the detection voltage of a detection electrode 2 is inputted to a discrimination circuit 4. The discrimination circuit 4 has the function for judging whether the lower end of the detection electrode 2 is present above or below a liquid level and is equipped with a variable resistor 6 for adjusting the amplitude of the detection voltage of the detection electrode 2, a condenser 7 permitting the passage only of the AC component of the output of the variable resistor 6, a reference voltage level control circuit 8 for adjusting the reference voltage level of the output of the condenser 7 and an inverter 9 inputting the output of the control circuit 8.
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