1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Transducer Piezo: Is it a buzzer?

Discussion in 'General Electronics Chat' started by Screech, Sep 24, 2003.

  1. Screech

    Screech New Member

    Joined:
    Aug 7, 2003
    Messages:
    345
    Likes:
    1
    Location:
    Melbourne Australia
    Is this transducer piezo a buzzer? :?

    I hooker it up to a 9 Volt. battery( black lead to negative and red to positive) but no sound came out.
    I then hooked it up to 12 volts, but no sound.
    What am I doing wrong?

    pic attached.
     

    Attached Files:

  2. kinjalgp

    kinjalgp Active Member

    Joined:
    Oct 28, 2002
    Messages:
    1,851
    Likes:
    3
    Location:
    INDIA/USA
    From what you say, I guess it is only Piezo-plate without oscillator circuit. For Piezo buzzer to make sound, it requires an oscillator with frequency of around 3kHz. This thing will work only after you connect a sine/square wave oscilaltor to it.

    Check this oscillator circuit from "CyberCircuits"
    http://www.uslink.net/~cybercir/cir8.htm
     
  3. Colin

    Colin Member

    Joined:
    Sep 25, 2003
    Messages:
    403
    Likes:
    22
    Location:
    Australia
    Piezo or Buzzer

    There is basically two different types of "piezo buzzers."
    One type has an electronic circuit inside the case and the other type consists of only a diaphragm.
    I distinguish between the two as follows:
    A piezo "buzzer" or "sounder" or "screamer" has an electronic circuit inside the case and when a DC voltage is applied (with the positive connected to the red lead) a sound will be produced by the device. This sound is generally a very loud high-pitched note but it can also be "beep-beep-beep" as used by trucks to indicate reversing.
    The other type of piezo device is called a PIEZO DIAPHRAGM.
    If you connect it to a DC voltage, you just get a very slight "click."
    It must be connected to a "signal."
    This "signal" can be almost any type of waveform (sinewave or square wave) with a frequency of approx 4 - 7 kHz.
    A piezo diaphragm will have a resonant frequency (such as 4.5kHz) and when this frequency is delivered to the unit, the maximum output will be achieved. As the amplitude of the frequency is increased, the output will also increase.
    The output of the diaphragm will also depend on the "quality" of the device and you can get a surprisingly good output from devices used in watches and Christmas cards.
    This brings me to the point of your question.
    The device shown in the photo is a PIEZO DIAPHRAGM and as such requires a driving signal.
    A simple oscillator (such as a square wave) from a Schmitt Trigger will drive the unit and if you use a more sophisticated circuit with parallel inductor, the output of the diaphragm will be "ear-piercing."

    I hope this is enough for a start.

    Colin Mitchell
     
    Last edited by a moderator: Sep 16, 2014
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. Screech

    Screech New Member

    Joined:
    Aug 7, 2003
    Messages:
    345
    Likes:
    1
    Location:
    Melbourne Australia

    Understood. :D
    so, I've connectted it to a 555 timer(is that ok).
    It's making sound.
    It's not loud but probably not in the 3-7 khz. range.
    I'm not using a resistor to it. Should I be using one?
    I'm using a nine volt battery.


    Thanks for your input guys. :)
     
  6. kinjalgp

    kinjalgp Active Member

    Joined:
    Oct 28, 2002
    Messages:
    1,851
    Likes:
    3
    Location:
    INDIA/USA
    Resistor isn't necessary.
     

Share This Page