1. Passive buzzers do not have an internal oscillation source, so they cannot be activated with a DC signal. A 2K~5K square wave is required to drive them.
2. The sound frequency is controllable, allowing for effects like "Do Re Mi Fa So La Ti."
3. In some special cases, they can share a control port with an LED.
Features of Active Buzzers：
1. Active buzzers have an internal oscillation source, so they sound as soon as they are powered.
2. They are easier to control programmatically; a simple high/low signal from a microcontroller can activate them, which is not possible with passive buzzers.
Module Description:
1. The module uses a 9012 transistor for driving.
2. Operating voltage: 3.3V-5V.
3. Equipped with mounting holes for easy installation.
4. PCB dimensions: 2.8cm x 1.3cm.
Module Interface Description (3-wire system):
1.+: Connect to an external 3.3V-5V voltage (can be directly connected to 5V or 3.3V microcontrollers).
2. -: Connect to external GND.
3. OUT: Connect to the microcontroller IO port.
Shipping List:
1. One active buzzer module as shown in the image (tested and functional).
