Water Level Detector

The following describes a useful module device for monitoring the water level in a tank or even a well.


  • at the low level T1 is blocked, the positive potential from the collector or through the resistor R7, opens the transistor T3 respectively the relay REL;
  • the transistors T2 and T3 form a bistable so that at the opening of T3 T2 is blocked, the level of the liquid begins to increase and reaches the electrodes that form S1, T1 opens, the potential in its collector disappears but the bistable maintains its state.
  • when the liquid reaches sensor S2, the base of T2 is polarized, the flip flops (T2 drives, T3 blocked), the relay is switched off.

Files for the project