A simple method for distinguishing active electromagnetic buzzers from passive electromagnetic buzzers.

The simple difference between the active buzzer and passive buzzer:

The fundamental difference between an active buzzer and a passive buzzer is that the product has different requirements for the input signal; the ideal signal for the operation of the active buzzer is DC, which is generally marked as VDC, VDD, etc. Because there is a simple oscillating circuit inside the buzzer, it can convert the stable direct current into a pulse signal of a certain frequency, and the magnetic field alternates from the surface to drive the molybdenum plate to oscillate and sound. However, some active buzzers can also work under specific communication signals, but the voltage and frequency of the communication signals are very high, and this kind of operation method is generally not used.

The passive buzzer has no internal drive circuit, some companies and factories call it a buzzer, and the national standard calls it a buzzer. Ideal signal square wave for passive buzzer operation. If the buzzer does not respond to the pre-DC signal, because the magnetic circuit is stable, the molybdenum sheet cannot oscillate and make sound.