Piezo Buzzer

Discussion in 'General Electronics Chat' started by chaos51, Jun 28, 2012.

  1. chaos51

    Thread Starter Member

    Jun 18, 2011

    I am a bit puzzled, I am trying to amplify an audio signal, with a lm386n-1, and I am sure I got the circuit right, as it amplifys loudly through my speaker.

    However putting a smaller and more convenient piezo buzzer in place of the speaker, gives me a soft signal, as if there was no amplification.

    I put the piezo buzzer directly on the sourcesignal, and the loudness is the same as it is after amplification.

    So what is so different in Piezo buzzer as from "normal" loudspeakers, that they seemingly ignore a amplified signal?

  2. WBahn


    Mar 31, 2012
    Many piezo buzzers are self-contained circuits and the two wires going to them are to provide power when you want the thing to make noise.

    What piezo buzzer, specifically, are you trying to use?
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Big difference in impediance , speaker about 8 Ω, piezo speaker, guess about 100k Ω; might use a 8 Ω to plate transformer to match ??
  4. Audioguru

    New Member

    Dec 20, 2007
    A piezo "buzzer" has a built-in oscillator.
    Maybe a piezo "transducer" (speaker) is used instead.
    A piezo transducer has a few high frequency resonances where it is loud but low frequencies are not produced. Frequencies between resonances are not loud.
  5. takao21203

    Distinguished Member

    Apr 28, 2012
    piezo is a lot like a capacitor.
    They need a discharge facility.

    And they are also often used with higher voltages.

    Sometimes coils are used for this purpose.

    Using them with direct DC drive only, it's helpful to put a resistor in parallel, 1K or the like, this will improve output.
    chaos51 likes this.
  6. chaos51

    Thread Starter Member

    Jun 18, 2011
    I am not sure really. I bought it locally, labeled as "Piezo Buzzer", with no more details then that. It's a black cylyndrical shape the size of a button, but thicker, and has the markings ZO and a tiny logo saying "M".
  7. chaos51

    Thread Starter Member

    Jun 18, 2011
    Thanks... That was helpfull.. Indeed the higher frequencies are pretty hearable, the low once are not. And yes you are right, it probably is a transducer and not a buzzer.