Here is a simple solution to prevent the wastage of water from overhead tank. It gives an audio visual indication when the water level rises towards the top of the tank so that the water pump can be switched off to prevent the overflow. This is also an ideal circuit to monitor the water tank with float valve operation.
LEDs form an inevitable part in the modern electronics as simple indicators to optical communication devices. Light Emitting Diodes exploit the property of the p-n junction to emit photons when it is forward biased. LEDs are specially made diodes to emit light when a potential is applied to its anode and cathode.