This document summarizes a water level indicator circuit that uses LEDs and a buzzer to indicate the water level in a tank. The circuit works by completing a connection through the water as each probe is submerged, causing the corresponding LED to light up. When the last probe connects, the buzzer will sound to indicate the tank is full. The document also describes a float-based system that directly measures the water level using a float and counterweight attached to a linear scale outside the tank.

2. INTRODUCTION
• This introduction is designed to determine the water
level especially in a water tank.
• As the level increases from the base from the tank
the number of glowing LEDS increases subsequently.
• Amount of water present in a water tank can be
easily measured.
• A direct measurement using float with pulley.

3. OBJECTIVES
This circuit has a number of practical uses in daily life.
• Now no need to go on roof to check the water level
• Can be used to measure underground storage of water.
• Water level indicator works to maintain a constant level.( Used in different
plants and industries)
• Alarm starts ringing as soon as tank full. it helps to check and wastage of
water by warning the person when the tank in about to brim.
• It can also be used to calculate incoming and outgoing water in large
reservoirs.
• It is used to predict the arrival of floods.
The direct measurement using the float with pulley is to show the feed
forward of the process
• It is the substitute for the indirect measurement
• It will also use to compare the measurement of the two method to conclude
which one is not working properly.

4. OPERATION
Circuit operations
• When any wire is dipped in water that wire will be connected to wire common
through water , establishing a negative voltage across the base of transistor.
Current begins to flow from collector. In this way LEDs will glow.
• After any successive connections of wires with common respective LEDs will
glow according to desired position in the tank. And when the last probe of the
buzzer will connected to the common or negative, then there will be sound
from the buzzer so it’s indicated that water attained maximum level and after
this water will flow over.
Float operations
• When the water increases the floating elements it will raise according to the
height of the water then a counterweight is hanging outside to indicate the
water level by leaning a linear scale.

5. CIRCUIT COMPONENTS LIST
• A1015 Transistor • 220 v AC Source
• 470 Ohm Resistor • #22 AWG
• 1k ohm Resistor stranded/solid Wire
• Sound Buzzer • +/- Binding Post
• Bridge Rectifier • Socket
• Transformer • A/C cord
• LED • 4x2x7” Plastic Case
• Toggle Switch

6. CIRCUIT
DIAGRAM

7. Transistor A1015
• This is key element in circuit. It is used as switch.
• The important property of this Transistor is this transistor
give output from collector only when its base voltage is
at some negative voltage emitter potential than its
emitter.
• As describe before, Transistor A1015 can only be turned
on if base is at low voltage than emitter. In order to set
the voltage below 12V we put 1k ohm resistor, setting
base to some low voltage.

8. Bridge Rectifier
• Bridge rectifier is actually a bridge of
diodes 1n4007.this is used to convert 12V
Ac from step down transformer to 12V dc
which is used to supplied to circuit.

9. LEDs
• Light emitting diodes, placed in circuit to show the
level per liter in the tank. These diodes are operated
at 1.5V

10. 470 Ohm Resistors
• 470 ohm resistors are installed in the circuit
because LED is operated at 1.5V and we are
having 4.7V in the circuit. So in order to decrease
the voltage across LED we placed 470 ohm in series.

11. 1k Ohm Resistor
• 1k ohm is connected to the base of transistor which
is the load of the transistor. So the base is expose to
the process to be connected in the other open
connectors which all negative.

12. Transformer
• It’s the opposite of the above, and would be used
to run for example a 110v product in a country with
a 220v mains supply.

13. Whole system process diagram

14. WHOLE SYSTEM PROCESS MATERIALS
• List and uses of every process materials
• Tank - it will holds the water to be measure
• ½ diameter Pipe including elbow, ball valve - Pipe (fluid conveyance), a hollow cylinder
following certain dimension rules.
• Float with pulley- this float has an indicator and a counterweight. The indicator slides up and
down on the outside of the tank and the counterweight are contained inside it. Only the float is
in contact with the liquid.
• Water level indicator circuit – it will makes the process to run.
• Illustration board with linear scale measurement – it will show the actual level measurement of
the water inside the tank.
• Power Supply – to supply reduced amount of electricity.
• Pump – A pump is a device used to move fluids, such as liquids, gases or slurries.
• Wires – Connection.
• Stand - to hold the tank.

15. GOODBYE