buzzer & transformer

Discussion in 'The Projects Forum' started by gatoulisss, Jan 31, 2015.

  1. gatoulisss

    Thread Starter Member

    Jan 23, 2015
    34
    0
    hello,
    i want to make a piezo buzzer much louder than it is, in many circuits im seeing transformers using like the siren in the picture any ideas how to do this?
    im taking the output of a pic16f88 as sound driver for the buzzer. Photo 31-1-15 - 10 20 21 μ.μ..jpg
     
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,854
    767
    If you have the board then you can draw the circuit, and how is the info of piezo buzzer?
     
  3. gatoulisss

    Thread Starter Member

    Jan 23, 2015
    34
    0
    i dont know how exactly the trasporter works... i understand that work to make the buzzer louder but how i can do it?
     
  4. Robartes

    Member

    Oct 1, 2014
    57
    13
    That circuit looks like a blocking oscillator. If so, I don't think the transformer in itself has anything to do with making the buzzer louder. One thing to watch out for with piezo buzzers is that they all have a specific resonant frequency at which they are the loudest, and usually fall off quite steeply on either side of that frequency. So to insure a piezo buzzer is loud, make sure you are driving it at its resonant frequency. The datasheet of your buzzer should tell you what that frequency is.
     
  5. gatoulisss

    Thread Starter Member

    Jan 23, 2015
    34
    0
    i have also this syren in the foto, the 2 yellow cables are the signal and the ground. thats why im thinking of the trasformer as amplifier but i dont know how it works
     
  6. ScottWang

    Moderator

    Aug 23, 2012
    4,854
    767
    The first photo with the photo in the 5# are different, I want make sure how is the circuit in the first photo, otherwise only can guess that and may not the same, if you took the first photo, could you take the picture for the solder side?

    If the circuit is similar as in the linked page from Robartes, then you can reducing the values of R1, or you can using a 1K in series with a 50K pot to replacing R1 to adjust the base current for bjt.
     
    Last edited: Feb 1, 2015
  7. gatoulisss

    Thread Starter Member

    Jan 23, 2015
    34
    0
    the first picture is from an alarm syren with no drive circuit you just give 9v and sounds the board is just making the sound, i post it to saw you that the buzzer is connected to the transformer... im interesting most of how it works so i can make something like picture in #5 wich is a normal buzzer but sounds much more than without the transformer
     
  8. ScottWang

    Moderator

    Aug 23, 2012
    4,854
    767
    You can google "pieze buzzer schematic" as this then you can find many circuits.
     
  9. Robartes

    Member

    Oct 1, 2014
    57
    13
    It is possible that the transformer's secondary winding has a higher number of turns than the primary so that the buzzer gets a higher peak-to-peak voltage and sounds louder. In the presumed circuit from post #1, this function would be combined with the oscillator function (the transformer serves in the oscillator circuit and increases output voltage). In the presumed circuit of post #5, the transformer would just increase the output voltage from an earlier oscillator stage.
     
  10. gatoulisss

    Thread Starter Member

    Jan 23, 2015
    34
    0
    so what type of transformer i sould buy and how i connect it so i have output voltage icrease?
     
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