I have an Arduino starter set, which came with both an active and a passive buzzer. Unfortunately, I can't seem to know which is which. All I know is that one is a little longer than the other one, on which I can see the green circuit board underneath.
35 Answers
An active buzzer generates the sound itself. You basically just turn it on or off. A passive buzzer needs a signal source that provides the sound signal.
To find out which is which you can measure the resistance between both leads. If it is a few Ohms its the passive one, higher values indicate an active one. Also the active one will have it's own circuitry (the pcb you can see) and will therefor be probably bigger.
But I guess your arduino package comes with a parts list that should give you all information you need?
1"Programatically" speaking:
- Active Buzzer: using a simple digitalWrite(buzzerPin, HIGH) will turn the beep on, once it has a internal oscillator.
- Passive Buzzer: you need to use Tone() function in order to make it beep. Once it has no internal oscillator you need to use Tone() function to create the frequency it will oscillate. Check the Tone() reference page to learn how to use it, but is quite simple, you just need to enter as parameter pin and frequency like Tone(3, 440), will generate a 440Hz on passive buzzer hooked up to pin 3.
To stop a active buzzer you need to use digitalWrite(buzzerPin, LOW), while with a passive buzzer you need to use noTone(passiveBuzzerPin).
How to distinguish passive buzzer and active buzzer?
There are several ways to distinguish passive buzzer and active buzzer. The most simple method is to watch their different appearances.If you can see a drive board,it is passive buzzer.If the buzzer is completely covered by black adhesive,it is active buzzer.
They come in all shapes and sizes, so don't assume "long" means one thing or another. The passive buzzer has only a small piezo on the module's PCB. An active buzzer will have a couple other small components on the pcb, like an amp and resistor(s).
In the Freenove Arduino kit that i bought, the passive buzzer is the one with the green on the bottom and the active is the one without, and is slightly taller with varied hights of the pins
