you can take an idea from it.

1. HAMDARD UNIVERSITY KARACHI (HIET)
DEPARTMENT OF ELECTRONICS (BE-LAB)

2. Introduction:
This circuit is designed to determine the water level
especially in a water tank.
As the water level increases from the base of the tank the number
of glowing LEDS increases subsequently.
Amount of water present in a water tank can be easily measured.

4. Components List:
Circuit elements used are as follow:
BC 548 Transistor.
330 ohm Resistor.
220 ohm Resistor.
Sound Buzzer.
LEDs.
9 V battery & its clip.

5. About Circuit Elements:
Transistor BC 548:

6. LEDs:
Light Emitting Diodes, Placed in circuit, to show
level of water in Tank. These diodes are operated at
1.5 V

7. Working of Circuit:
• When any wire is dipped in water that wire will be
connected to wire N through water, establishing a
negative voltage across the base of transistor. Current
begins to flow from collector. In this way, LED glows.
• After successive connections of wires with N,
respective LEDs will glow, and when wire C will be
connected to N , then there will be sound alarming you
that water has attained maximum level and after this
water will flow over.

8. Applications of Circuit:
This Circuit has a number of practical uses in daily life.
Now no need to go on the roof to check the water level.
Can be used to measure underground storage of water.
Water level Indicator works to maintain a constant water
level.
(Used in different Plants and Industries)
Alarm starts ringing as soon as tank becomes full.
It helps to check overflow and wastage of water
by warning the person when the tank is about to brim.