Easy Electronics projects

water level indicator circuit using Transistor

We generally worry about the wastage of water, when we switch ON the motor and forget to turn it off. The Water Level Indicator employs a simple mechanism to detect and indicate the water level in an overhead tank or any other water container.We have posted already a Water Level Indicator and Controller using IC ULN2003. In this article we are presenting a very useful, cheap and a simple circuit using transistors (bc547) for beginners. This circuit indicates the level of water in water tank using LEDs with transistors. you can use this project as college project.

Circuit Components

Circuit Diagram

water level indicator using transistor

The connections arrangements shown in the circuit diagram shown aove. The +9V power supply or battery is used. In this circuit we have used all the transistors as a switch. The water touches the wires contact with base of each transistor, a small current flows through the base and turns on the transistor as transistor turns on, LED connected to it glows. LEDs will be turned on depending up on the level of water. We have used a buzzer with last transistor as water touch the base of last transistor collector the collector and emitter connected and buzzer rings. Relay can be connected instead of buzzer to auto control the water level in the tank.

Points of BC 547

BC547 transistor points

Resistor 220 Ohm

220ohm resistor

Applications & Uses Of Water Level Indicator

  • Water tank level control
  • Automatically turn ON/OFF water pumps
  • It is used in factories, commercial complexes, apartments, home,
  • Fuel tank level indicator
  • Oil tank level control and indicator
  • High & low level alarms
  • Pool water level control
  • Leach-ate level control
  • Cooling tower water level control
  • Sewage pump level control
  • Remote monitoring liquid
  • Pump controller Auto
  • Stream level monitoring auto

Watch video for practical 



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