DIY Water Level Indicator using BC547 NPN Transistor

Let’s get started with a very useful project which is a Water Level Indicator. Nowadays, almost everyone has an overhead tank in their home. However, anyone who owns a water tank above ground is familiar with the issues that they face like water tank overflow as well as tank exhausting without any previous clue. Most of the time water starts spilling out of the tank which shows wastage of water and energy. 

Components Required

Introduction to BC547 NPN Transistor

Introduction to BC547 NPN Transistor, BC547 pins, BC547 symbol

BC547 is a Bipolar Junction NPN Transistor. It is primarily used for switching as well as amplification. BC547, like the other transistors, is used for current amplification. The smaller current at the base is used to control the larger currents at the collector and emitter.

Characteristics of BC547 NPN Transistor

  • DC Current Gain (hFE) is about 110-800
  • Continuous Collector Current (IC) is 100mA
  • Emitter Base Voltage (Vbe) is 6 Volts
  • Collector Emitter Voltage (Vce) is 30V
  • Collector Base Voltage (Vcb) is 30V
Wires  are submerged in the tank at different levels with one common VCC wire and the input simply goes to a transistor to turn on an LED, A buzzer can also be used at bottom or top level. Selection of probe material is important as the very low current flowing through them in liquid medium, submerged sensor wires are prone to corrosion and calcification by the minerals present in water. As a result, they cease to function properly after a few months or a year. So, you can use graphite probes for your sensor.


Circuit Diagram

circuit diagram for Water level indicator
Diy projects


Kapil Kumar

Kapil Kumar

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Nice! I will try to make this for my water tank.

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