Source: https://mokxi.com/parts/buzzer Updated: 2026-09-27 Part # Buzzer Sounds when it is driven, and shows it on screen. or see every part - 2 pins Drawn live by the editor's own code, at the size you see it. Reference ## Every one of its 2 pins Pin What it does 1 The longer leg, positive. 2 The shorter leg, negative. This part ## What it does Mokxi models the ordinary small piezo buzzer that most kits ship, the active kind with its own oscillator built in, rather than a bare speaker element. Electrically it behaves like a polarized resistor: it conducts, and sounds, only while its longer leg sits above its shorter one, and it goes high-impedance the moment it is reverse biased or left with either leg floating. There is no audio waveform in the model, only a sounding-or-not state and the current it draws while it does, which is enough to show the one mistake almost everyone makes with this part: put the usual 220 ohm "LED resistor" in series with it and the divider that results leaves too little voltage across the buzzer to sound at all, so it goes silent rather than merely quieter. People wiring a buzzer for the first time often assume it has failed; here the same current probe that explains an LED’s brightness explains why the buzzer has gone quiet instead. How it is modeled ## What is true about the Buzzer, here ### What is modeled The buzzer really loads the net it is on, the same way the LED does, and that matters for a common mistake: driven straight off a 5 V rail it takes about 31 mA and sounds, but with the usual "LED resistor" of 220 ohms in series, the divider it forms leaves only around 2 V across it (below the threshold it needs), so it goes silent rather than merely fainter. ### Not modeled No audio waveform and no volume. The probe reports sounding or not sounding, nothing in between, and no reverse current or capacitance either. The two numbers behind that are both round rather than measured from one part. The element is a plain 160 ohm resistor while it conducts, which is the round number next to the 167 ohms a 12 mm 5 V buzzer's rated 30 mA at 5 V works out at, so it draws 31 mA on a stiff rail. It is called sounding at 2.5 V across it and silent below, which is half the rated supply and stands in for the 3 V to 8 V operating range those datasheets quote. A real buzzer fades out over a volt or so rather than stopping at a line. There is no frequency at all: a real active buzzer's note is somewhere near 2.3 kHz and this part has none. From Buzzer (active), in full. Projects ## See the Buzzer in a project Shown here on: Arduino Uno R3 Learn ## Where it turns up in a lesson ### In the twelve week course - Week 11: Interrupts: events instead of polling ### In a learn article - Arduino Ultrasonic Sensor (HC-SR04) Tutorial - Arduino Science Fair Projects With a Real Hypothesis - Reaction Time Science Fair Project With an Arduino More parts ## The rest of the bench Every one of these is drawn and simulated the same way. Full-size breadboard A real 0.1 inch grid with the rails and the center channel, 63 columns wide. Jumper wires Drag from any pin or hole to any other. Corners snap, and you can drag them. Power A supply rail at the voltage you choose. Ground The other end of every circuit. LED Lights when current flows. Five colors, and the brightness is what your eye would see. Resistor Any value you like, with the color bands drawn to match. ESP32-C3-DevKitM-1 A RISC-V board that runs your firmware at 160 MHz on the real memory map. Pushbutton A 12 mm tactile switch. Hold it while the simulation runs. Raspberry Pi Pico The RP2040 board on our own Cortex-M0+ core. Pick a program and press Run. Raspberry Pi Pico W Raspberry Pi Pico W (RP2040). The same board and the same pinout as a Pico, with the CYW43439 on it. The WiFi is simulated (no radio, no real internet), and the on-board LED, which hangs off that chip rather than off GP25, is driven through the same path. Everything else is the Pico. STM32F411 Black Pill The Black Pill on our own Cortex-M4 core. Pick a program and press Run. BBC micro:bit V2 The nRF52833 board with its 5x5 LED matrix, buttons A and B and a speaker. Wire the rings to a breadboard. See every part ## Wire up the Buzzer Open the editor and push it into the breadboard. It is free, and it runs on your own machine. Start building Open the editor