| 摘要 |
PURPOSE: A method for detecting water level of a water purifier is provided to detect the water level of the water purifier with a detector installed in an external wall of a water tank and without directly contacting the detector with water. CONSTITUTION: A method for detecting water level of a water purifier includes the steps of forming a non-stable multivibrator by transistors(Q1,Q2), boosting the voltage of the non-stable multivibrator with a high frequency transformer(L1), applying the current to an electrode plate for transmitting(11b), amplifying the signal of an electrode for receiving(11a) by a transistor(Q3), receiving the output from an emitter resistance(R3), changing the signal into the direct current signal by condensers(C4,C6) through a detection diode, and applying the voltage to a minus terminal of a voltage comparing device(U1), so that the voltage applied to the minus terminal becomes lower than a reference voltage divided by resistances(R4,R5) and drives a relay driving transistor(Q4) for operating a relay(R), while the voltage applied to the minus terminal becomes higher than the voltage applied to a plus terminal. If the output is low, the relay output is interrupted, such that the level of water is exactly detected.
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