I have already discussed many water level monitoring devices which may be effectively used for controlling or for just keeping a watch over the rising water levels inside an overhead water tank.
All these circuits though work on a basic principle of detecting the water levels by sensing the conduction of current through the water for triggering the electronic circuit associated, the present has one striking advantage.
All these previous circuits incorporated external buzzers or sound generating equipment for the required alarm outputs. Here the circuit itself is an oscillator and is able to produce buzzing sound, once its time determining componentwhich happens to be a resistor is connected. However this resistane value is not an actualt resistor rather the water