What are the advantages of using a passive buzzer? The passive buzzer uses the electromagnetic induction phenomenon to make sound for the electromagnet formed after the voice coil is connected with the alternating current to attract or repel the permanent magnet to push the diaphragm. The direct current can only continuously push the diaphragm without producing sound, and can only produce sound when connected or disconnected.

The working principle of passive buzzer is the same as that of loudspeaker.
When using square wave signal source to drive, a diode shall be connected in reverse parallel to prevent the high-voltage reverse electromotive force generated in case of sudden power failure from penetrating other components and shortening service life.
Active buzzers are often more expensive than passive ones, because there are multiple oscillation circuits in them. They only need to be connected to the DC of rated voltage to send out the sound of specified frequency. The frequency is determined by the internal oscillation circuit and cannot be changed.
1. Low production cost;
2. The sound frequency range is wide, which can make the effect of "dolemifa solasi";
3. In some special cases, a control port can be multiplexed with an LED.