Water tank level indicator

WATER TANK LEVEL INDICATOR

AIM

To construct a circuit to know the level of water tank with the help of Transistor BC547 and LEDs.

Component required

Sl no	Component	Specification	Quantity
1	Transistor	BC547	3
2	LED	Any color	3
3	Resistor	220 Ω	1
4	Power supply	9v	1

Theory

Water tank overflow is a common problem which leads to the wastage of water. Really you don’t want to climb your roof again and again to check the water level, whether the tank is empty, half or full. Though there are many solutions to it like float valves which automatically stop the water flow once the tank gets full. But being electronics enthusiastic wouldn’t you like an electronic solution for it? So here is a simple, handy and cheap way that will guide you to make a circuit which will detect the water level of tank. 

 This simple transistor based water level indicator circuit is very useful to indicate the water levels in a tank. Whenever tank gets filled, we get alerts on particular levels. Here we have created 3 levels (low, medium and high). We have added 3 LEDs to indicate initial three levels low medium and high.

BC547

BC547 is a bi-polar general purpose NPN transistor that is commonly used in switching and amplifying applications. It can found in relay driver, LED driver and other medium power switching devices and audio or signal amplifiers. The pin configuration of BC547 is:-  

Circuit diagram

Design calculation

Working principle

Here we are using transistor (of NPN type) as a Switch. Initially there is no voltage applied to the base of the Transistor T1 and the transistor is in OFF state and no current is flowing through collector and emitter and LED is OFF

When the water level reaches to low level Point in the tank, the positive side of the battery gets connected to the base of the Transistor T1 through the water. So when a positive voltage has been applied to the base of the Transistor T1, it gets into ON state and current starts flowing from collector to emitter. And RED LED glows.

Same way when the water level riches the medium level of tank the T2 transistor get switched and the blue LED glows

And finally when the water tank gets full the T3 transistor get switched and the green LED glows.

We can also connect a buzzer so that when the tank gets full, buzzer will create an alarm.

Conclusion

Circuit for water level indicator of tank is been constructed and observed the output.

Watch video 

https://youtu.be/j20ryQXTw6g