In fact, to distinguish between active and passive buzzer, a variety of methods, the simplest appearance recognition, you can see the green of the drive plate is passive buzzer, completely enclosed with black glue is active buzzer, see the word "SWT" is passive, with stickers sealed sound hole is active.
Another method is to use a battery with a wire connecting terminal respectively touch the buzzer, if every touch has Chi sound, that is passive. If only a ring, or silent, it is active.
The characteristics of passive buzzer with voice controlled, can emit different frequencies of music buzzing sound, but it also has a shortcoming that is not directly on the drive, external drive device.
The most common active and passive buzzer buzzer, a small majority belongs to passive buzzer, especially less than 10MM in diameter, the active buzzer is very small, and even can be said that each company with active buzzer passive buzzer is not proportional to the passive buzzer to much more.