Stupid Piezo Question

Discussion in 'General Electronics Chat' started by Jim_2.0, Feb 23, 2009.

  1. Jim_2.0

    Thread Starter Well-Known Member

    May 14, 2006
    51
    0
    Ive never used a simple piezo buzzer before...

    Ive got one on my bench to play with, but cant seem to make up my mind on the results. How do i adjust volume, or can i not? ie i have a piezo with rated voltage range 3-28V, freq 3kHz, supposedly 90dB. Ive tried a 5V square wave, and 24V square wave with no real difference. Seems nowhere near 90dB to me. Does the frequency of the wave control volume, or do you not control volume? just tone? confused :(. Ive checked my piezo is definitely not built in oscillator type either
     
  2. ecb123

    New Member

    Mar 6, 2008
    7
    0
    You say it is a piezo buzzer not a piezo transducer-this implies that the device has a built in oscillator-you should then energize the buzzer with 3-28 volts dc-not a pulsed squarewave.
     
  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    If it is a piezo transducer in a plastic resonating chamber like my pic then it is the loudest at only one frequency.
    It is rated at 90dB at a distance of only 10cm, not 1m like speakers.
     
  4. bertus

    Administrator

    Apr 5, 2008
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  5. Jim_2.0

    Thread Starter Well-Known Member

    May 14, 2006
    51
    0
    ok this all sort of makes sense. it must be a piezo transducer i have, cos i get no noise unless i pulse the thing. i did find the resonant frequency spec of 3khz, and lo and behold when i pulse it at that frequency its at its loudest. interesting about the 10cm thing, i didnt realise that... the application needs a very loud keypad beeper, because the unit will be working beside trucks and large machinery, operators are asking for a loud beep when they press a button. any other devices that may be suitable?
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    There are piezo beepers with two zones on it.
    One small zone for low intensity sound and a large zone for high intesity sound.

    Greetings,
    Bertus
     
  7. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    If sound intensity is critical, you may what to consider a sounding device made by Sonalert. Some of these units only need you to apply the operating voltage and they will produce a sound that is loud enough to overcome the environmental noise you mentioned.

    Website is: http://www.mallory-sonalert.com/.

    hgmjr
     
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