The appearance of active buzzer and passive buzzer is shown in Figures A and B. ..
Figure: Appearance of active and passive buzzers
A) active b) passive
From the appearance of Figure A and Figure B, the two buzzers seem to be the same, but look closely, the heights of the two buzzers are slightly different. The height of active buzzer A is 9mm, and the height of passive buzzer B is 8mm. For example, if you put the pins of two buzzers up, you can see that one with a green circuit board is a passive buzzer, and the other with a vinyl seal without a circuit board is an active buzzer.
Judge the active buzzer and passive buzzer in one step, or use the resistance file Rxl of multimeter to test: connect the buzzer-pin with a black stylus, and touch the other pin back and forth with a red stylus. If the buzzer is triggered and the resistance is only 8 Ω (or16 Ω), it is a passive buzzer; If it can emit continuous sound and the resistance is above several hundred ohms, it is an active buzzer.
The active buzzer can continuously sound when directly connected to the rated power supply (the new buzzer is indicated on the label); Passive buzzer, like electromagnetic speaker, needs to be connected with audio output circuit to make sound.
The difference between active buzzer and passive buzzer;
Note: The "source" here refers not to the power supply, but to the vibration source.
In other words, the active buzzer has a vibration source inside, so it will sound when it is energized;
Passive has no vibration source inside, so it can't be chirped by DC signal. It must be 2K-5K square wave drive.
Active buzzers are often more expensive than passive buzzers because there are many oscillating circuits inside.
The advantages of passive buzzer are:
1. Cheap
2. The sound frequency can be controlled, and the effect of "Domi doing Solarxi" can be achieved.
3. In some special cases, the control port can be reused with LED.
The advantages of active buzzer are: convenient program control.