This Simple Water Level Indicator Buzzer Circuit show how much water is inside the tank and also it make beep sound like alarm when water become too high or too low.
Also, we can make this circuit using transistor and some other small electronic parts, however, it only beep when water touch two metal pieces placed inside the tank.
In this post, the circuit explain how to make it and also, it tell what things are good in it and what things are not so good.
Circuit Working:
Parts List:
| Components | Values | Quantity |
| Resistor | 10Ω 1/4 watt | 1 |
| Semiconductors | Transistors BC547, BC557 | 1 each |
| Speaker 8Ω | 1 | |
| Power Source +3V to 6V | 1 | |
| Water level probes like any metal probes | 1 |
First, we need to understand what parts this circuit uses and how they connect.
- First, +3V power connects to emitter of BC547.
- Next, collector of BC557 connects to base of BC547.
BC557 Transistor:
- After that, collector of BC557 connects to ground using 10 ohm resistor.
Speaker:
- Also, 8 ohm speaker connects between emitter of BC547 and ground 0V.
Water Level Probes:
- Finally, connect the water probes to the base of the BC547 and the +3V power wire.
Formulas:
However, to make water level buzzer circuit we have used simple circuit and also used below formula.
How to find BC557 base resistor:
Also, this resistor stop too much current from going to base of BC557 and it helps transistor work good and stay safe.
Formula:
R1 = (VCC − VBE) / IB
where:
- VCC is power and in this circuit it is 3V.
- VBE is voltage drop from base to emitter which is usually around 0.7V.
- IB base current needed for transistor to work.
Speaker resistor to limit current:
Additionally, one resistor also needed with speaker and it stop too much current going to speaker or BC547 transistor as it protect both.
Formula:
R2 = VCC / Ispeaker
where:
- VCC is 3V.
- Ispeaker is how much current speaker need which is usually 20 to 30 mA for small speaker.
To begin with, these formula help to make working circuit, but remember the real resistor values and transistor may be little different.
Therefore, check datasheet or test circuit and change if needed to make the circuit working.
Working of the Circuit:
At first, BC547 transistor work like a switch it control how mush current move in the circuit, when no water touch the probes the base of BC547 gets no signal and so transistor stay OFF.
After that, the BC557 transistor works as a voltage divider with a 10 ohm resistor which connects to ground and allows current to flow when water bridges the probes.
Also, an 8 ohm speaker connects the BC547 emitter to the ground and when water touches the probes, it completes the circuit.
Lastly, the current flow through BC547 and it turn ON and speaker make sound.
How to Build:
- First, collect all parts we need.
- Next, put BC547 and BC557 transistors on PCB board.
- After that, connect emitter of BC547 to +3V power.
- Then, join base of BC547 to collector of BC557.
- Also, connect collector of BC557 to ground using 10 ohm resistor.
- After that, connect 8 ohm speaker between emitter of BC547 and ground.
- Finally, use +3V wire and base of BC547 as water probes.
Note:
Lastly, check all the wires, ensure there are no loose connections and connect the circuit correctly.
Conclusion:
This Simple Water Level Indicator Buzzer Circuit is easy way to check water level in many uses.
Also, users can build this circuit and use it for their own work once they understand how the parts connect and function