An active buzzer sensor module has a built-in oscillation circuit, thus the sound frequency is fixed. It is able to generate the sound itself. So, you can simply turn it on and off with an Arduino pin, just like the way of turning on and off a Led which is connected to Arduino board. Besides, this sensor starts beeping when it is being supplied with DC power supply.
Specifications:
- Operating voltage: 3.3V to 5V
- Active low sensor module
- Driver transistor: S8550
- Size: 3.2cm x 1.3cm