This document describes a water level indicator circuit that uses LEDs and a buzzer to measure the amount of water in a tank. As the water level rises, more wires submerged in the water will close circuits, causing additional LEDs to light up to indicate the increasing water level. When the highest wire makes contact, the buzzer will sound to signal that the tank is full. This simple circuit allows users to easily monitor and maintain the water level without having to check the tank directly. It has various applications for measuring underground water storage or controlling water levels in industrial plants.

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.