Difference between passive and active buzzers

What is the difference between Passive and Active Buzzers
Passive Buzzer
Uses a digital IO pin, which must be pulsed on-off as a square wave up to about 5KHz. The
module may use a transistor to provide some amplification of the sound, in which case it will
require power from the Arduino board.
With a "passive" device or speaker, you have to send it an AC "sound signal" and you can
control the sound. The Arduino needs to generate the "tone". With enough hardware and
software you could make it play musical notes. The only downside (besides a bit of extra
programming) is that it takes processor-time to generate the sound. This could be an issue if
your program (sketch) is doing lots of other things at the same time.
A piezo speaker can be driven directly from the Arduino (probably with a series resistor). A
regular (voice coil) speaker takes more current and it needs an amplifier (transistor).
Passive buzzer height of 8mm
Active Buzzer
An active buzzer can operate as a passive buzzer using a digital IO pin, but it can also operate
by using an analog pin (using analogwrite). The buzzer stays on once the signal is written
(keeps playing, unlike a passive buzzer which stops when the signal stops).
An "active" buzzer generates the sound itself. So, you can simply turn it on & off with an
Arduino pin, just like you turn on & off an LED.
However, most buzzers require a bit more current so you'll need a MOSFET to boost the
Active buzzer height 9mm
To determine if an active buzzer and passive buzzer
Use a multi-meter set to resistance
Black lead to buzzer "+" pin
Red lead back and forth on another pin
If this triggers sound, and the resistance is 8Ω (16Ω) it is a passive buzzer
If this triggers a continuing sound, and the resistance is more than hundreds of Ohms,
it is an active buzzer
An active buzzer directly connected to the rated power will be continuously audible whilst the
passive buzzer and electromagnetic speaker will need to be connected all the time to the
audio output circuit to generate sound.