Piezo Buzzer

A two-terminal piezoelectric buzzer that turns a PWM square wave into audible tones and alerts.

What is the Piezo Buzzer?

The piezo buzzer is a compact actuator that converts an electrical signal into sound using a piezoelectric ceramic disc. It has just two terminals, + (Signal) and - (GND), and measures about 12 x 8.5 x 12 mm, making it easy to drop onto a breadboard or panel. It runs at a 5V nominal drive level and tolerates up to roughly 12V, so it works directly from common 3.3-5V microcontroller logic.

This is a passive piezo element, which means it has no internal oscillator and produces no sound from steady DC. You feed the + pin a PWM or square-wave signal, and the frequency of that signal sets the pitch. On Arduino the tone() function generates the waveform for you, letting you play single beeps, alarms, or full melodies. The piezo is loudest near its mechanical resonant frequency, which for buzzers of this size sits in the low-kilohertz range where the human ear is most sensitive.

Because the piezo element is essentially a small capacitor, it draws only a few milliamps and can be driven straight from a microcontroller pin without a transistor or amplifier. That makes it a go-to part for user feedback: keypress clicks, low-battery warnings, timer alarms, proximity alerts, and simple music. Its sound is thin and sharp rather than rich, which is exactly what makes it cut through as an alert.

Specifications

Operating voltage: 5 V (max 12 V)
Dimensions: 12 × 8.5 × 12 mm

Verified from the Tinkered component library.

Circuit requirements

Wire the + (Signal) pin to the driving output pin and the - (GND) pin to the board ground; both pins are passive with no internal electronics.
Drive a passive piezo with an alternating signal, not steady DC. Use tone() or a PWM square wave; holding the pin HIGH produces at most a single click, not a continuous tone.
The piezo element is capacitive and draws only a few milliamps, so it can be driven directly from a digital pin with no series transistor or flyback diode required.
For louder output or to drive it toward its higher voltage limit (up to about 12V), switch the buzzer with an NPN transistor or small MOSFET from a separate supply, and keep that supply's ground common with the microcontroller ground.
On the Arduino Uno, tone() uses Timer2, so calling it disables analogWrite() (PWM) on pins 3 and 11 for the duration of the tone.

Board compatibility

The Piezo Buzzer connects to any of the microcontrollers supported in Tinkered. Mind the 5 V logic level on 3.3 V boards.

Common Piezo Buzzer mistakes

Using digitalWrite HIGH instead of tone()

A passive piezo needs an oscillating signal. Setting the pin permanently HIGH charges the element once and you hear only a faint click. Use tone(pin, frequency) or a PWM square wave to get a sustained sound.

Confusing a passive piezo with an active buzzer

An active buzzer has a built-in oscillator and beeps at one fixed pitch whenever it gets DC. This passive piezo has no oscillator: it stays silent on DC but can play any pitch you feed it. Running active-buzzer code (plain HIGH/LOW) on a passive part gives no tone.

Trying to set pitch with analogWrite()

analogWrite() outputs PWM at a fixed hardware frequency (roughly 490 or 980 Hz) and only varies duty cycle, so it cannot change the note. Use tone() to control the frequency (pitch) instead.

Expecting speaker-level volume

A bare piezo disc is intentionally quiet and thin-sounding. It is meant as an alert, not audio playback. If you need it louder, drive it near its resonant frequency and/or switch it through a transistor from a higher supply voltage.

Forgetting tone() blocks PWM on pins 3 and 11

On the Uno, tone() commandeers Timer2, which also controls PWM on pins 3 and 11. If you are dimming an LED or driving a motor on those pins, tone() will disrupt them until noTone() is called.

Popular Piezo Buzzer projects

Melody and ringtone player

Use tone() with an array of note frequencies and durations to play songs, jingles, or startup chimes from a single output pin.

Ultrasonic distance alarm

Pair the buzzer with an HC-SR04 sensor and beep faster as an object gets closer, a classic parking-sensor or proximity-warning build.

Countdown and kitchen timer

Sound an alarm pattern when a timer reaches zero, combined with a button to start and an LCD or 7-segment display for the countdown.

Reaction-time game

Flash an LED, start a millis() timer, and buzz when the player presses the button too early or reacts, scoring their response speed.

Keypad and UI feedback beeps

Add a short confirmation beep on each button or keypad press and a distinct error tone for invalid input to give tactile projects audible feedback.

Build with the Piezo Buzzer.

Drop the Piezo Buzzer into a circuit, write firmware, and simulate it in your browser, then deploy to real hardware. All in one editable Tinkered project.

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