An overflowing tank can be a total menace and difficult to control and by the time we reach for the tap, it’s already flooded and everything’s drenched wet. Water level controllers are perhaps the best equipments to handle the situation which instantly switches off the motor and pump stopping the tank from overfilling.
However, installing water level controllers can be complicated and a costly affair. A much simpler alternative is to use a device which instead of doing complex operations will just produce a sharp warning tone so that the user may be able to immediately to each the spot
The present design is intended exactly for the above reason. The circuit may be understood with the following points, please refer the CIRCUIT DIAGRAM to exactly learn
The two transistors are configured in a kind of feedback loop which starts oscillating when the relevant points are connected with the capacitor and the resistor.
However the circuit requires two resistors for making the above function possible. The second resistor is formed by the water which when comes across the two prods produces a resistance of around 150K, just perfect to generating a high pitch oscillating frequency.
This oscillating frequency is fed over to a speaker which instantly converts the oscillations into sound vibrations that can be heard over a long distance.
The above action takes place only when the tank reaches a predetermined level before overflowing.