Simple Piezo Buzzer Circuit

This Simple Piezo Buzzer Circuit make sound in new way, as it is easy to make and need only few parts like:

• One transistor which works like small switch
• One coil is like a tiny electromagnet
• One small speaker part and a piezo transducer to change electricity to vibration

Also, to make high sound like a whistle, this circuit is special because coil makes the sound to keep going and is not like other circuit with resistor and capacitor only.

What is a Piezo Buzzer Circuit:

A simple electronic circuit that makes sound using a piezo buzzer is called a piezo buzzer circuit also people mostly use it in electrical devices to give sound alerts, alarms or beeps.

Moreover, main part of piezo buzzer is piezo element which make sound by shaking when voltage goes in.

Circuit Working:

Parts List:

Components	Values	Quantity
Resistors	100k CFR	1
	4.7k CFR	1
Semiconductors	Transistor BC547	1
	Buzzer Inductor	1
	Piezo 3 Pin	1

First, when we look at piezo buzzer circuit diagram above we see transistor T1 and inductor are main parts.

The piezo used here has 3 pins, the middle pin gives feedback and we can place the buzzer coil properly to make the sound stronger.

Also, transistor turn ON when power comes in and this makes piezo element work with the coil and then transistor and piezo turns OFF fast.

The middle pin of piezo send signal to ground and this stop the transistor and after this transistor turn ON again then this cycle keep happening which make buzzing sound again and again.

Furthermore, middle pin of piezo is also very important because without it sound does not work well.

That is why we need a 3-pin piezo not a 2-pin one.

The coil get signal from transistor and fill with magnetic energy, then coil release this energy to make strong AC.

Then this AC connect to piezo pins positive and negative sides and make piezo vibrate fast and loud like sharp whistle.

Also, we must fix the piezo properly inside the case to make the sound louder and to get the correct sound frequency, the circuit works like a crystal oscillator and the piezo acts like a ceramic crystal.

Hence, it is hard to know exact frequency but design work like crystal oscillator and for best result piezo should touch bottom of case and case need a small hole to about 7mm wide for sound to come out.

Formulas:

Below is easy formula for Simple Piezo Buzzer Circuit:

Resonance frequency happens when the circuit works best with AC (changing current) for that we use following formula:

Frequency = 1 / (2π√(L × C))

where:

• f is frequency in hertz Hz
• 2π means 2 times pi a math number about 3.14
• √ means square root
• L is inductance and how much coil resist changes in current in Henry H
• C is capacitance how much capacitor store energy is in Farad F

How to Build:

Below are easy steps to build a Simple Piezo Buzzer Circuit

• First, put NPN transistor T1 on breadboard.
• Next, connect ferrite inductor to collector pin of transistor.
• Then connect 3-pin piezo transducer to base and emitter of transistor.
• After that add resistors and capacitors like shown in circuit diagram.
• Also, use wires to join all parts as per the circuit.
• Lastly, connect power supply to right place on breadboard and be sure voltage is correct for circuit.

Piezo Transducer Installation:

• First, take small box and make hole in it of about 7mm wide.
• Then put 3-pin piezo at bottom of box.
• After that place soft rubber ring on piezo the ring should be 30% smaller than piezo.
• Also, use glue to fix piezo and ring in box and check they stay in right place.

Testing and Adjust:

• Turn ON the power and watch how the circuit work.
• If circuit is good we can hear buzzing sound from piezo.
• If we want different sound then change resistor or capacitor value.
• To make sound louder then move piezo inside box little bit until sound better.

Note:

• We can make simple piezo buzzer that gives special sound and feedback by using these steps.
• We can change the circuit to get the right frequency.

Conclusion:

Simple piezo buzzer circuit is very easy and quite useful as it uses few parts like battery, resistor and piezo buzzer.

When current flows, the buzzer makes sound and this circuit costs low and we can build it easily.

Moreover it is good for beginners to learn basic electronics, overall, it is small but helpful circuit for sound indication.