This is very useful circuit.circuit designed by using very famous ic NE 555 and PN 2222 transistor.The circuit is completely automatic which starts the pump motor when the water level in the over head tank goes below a preset level and switches OFF the pump when the water level in the over head tank goes above the full level. Probe D is positioned at the bottom level of the tank while probes A, B and C are placed at full, half and medium levels of the tank respectively. The level sensing part of the circuit is built around transistors Q1, Q2 and Q3. When water level is below the quarter level probes A, B and C
