Why do active buzzer have the label “Remove after washing” on it?

Have you noticed this sticker on the buzzer? Why isn’t this sticker on the passive buzzer. Active refers to the built-in vibration source in the buzzer, which only needs to be powered on to produce sound.

Vibration sources are sensitive components, and whether the soldering flux used for circuit board welding or the cleaning agent used for plate cleaning, they will have an impact on the frequency of the vibration source after contact.

Stickers can protect the buzzer during the welding process until it is torn off after the circuit board is cleaned, while passive buzzers do not come with vibration sources and control their sound through external frequency input. Therefore, it is generally the active buzzer that gets stuck with stickers, which is why we see the bottom of the active buzzer sealed, while passive buzzers do not..