Warning Buzzer & Chime
The characteristics of a passive buzzer are:
1. Passive internal without vibration , so if it cannot be beeped using DC signal, it must be driven by 2K-5K square wave
2 The sound frequency can be controlled, which can make the effect of "multi-meter hair sorasi".
In some special cases, a control port can be reused with an LED
Active buzzers are characterized by:
1 The active buzzer has an oscillation inside, so it will call as soon as the power is applied
Convenient program control, the microcontroller can emit sound at just one high or low level, while a passive buzzer cannotEach set weighs about 6g.One module description
2 Working voltage 3.3V
6. There are fixing bolt holes for easy installation.
Two; Module Interface Description (3-wire system)1 VCC external 3.3V
2 GND external GND
3 I/O external microcontroller IO port

1 passive buzzer module (test passed)