Help with driver circuit for ultrasonic piezoelectric speaker

Discussion in 'The Projects Forum' started by hiya1432, Jan 30, 2012.

  1. hiya1432

    Thread Starter New Member

    Jan 30, 2012
    Hi this is my first post so i'll try to be detailed.

    For a school project I'm looking to make a circuit that will amplify a 58-60 kHz signal to be sent to a piezoelectric speaker (datasheet for the speaker is here
    My team has already made a circuit for the oscillator by using 555's, so I'm just wondering about amplifying the signal so it can be used properly by the speaker. We're working with a 9v battery and I was wondering the best way to complete this. I know in the speaker datasheet it has a test circuit, but I was also wondering if there is a way to design a circuit without a transformer. If not could someone recommend a specific one that could be used on a breadboard.

    Thank you for your time,
  2. mcasale

    Active Member

    Jul 18, 2011
    I've never used a speaker like the one you have here, but just assume right now it's just a capacitive load (1600pF). At 60KHz, that translates to a 1.66K Ohm impedance. If you drive it with a 9V square wave, that means you need to source 5.4mA from the electronics.

    So, depending on what signal you want to send to the speaker, you may only have to buffer the 555 output.

    You need to be more detailed in what you want to send to the speaker (amplitude, sine or square waves). I'd think that driving square waves into a capacitive load can create some annoying current spikes.
  3. hiya1432

    Thread Starter New Member

    Jan 30, 2012
    We're trying to have the speaker send out a 60 kHz signal (rectangular or sine wave) to three other receivers. The receivers only need to acknowledge that a signal was received because we are ordering the receivers from closest to furthest from the speaker based on which receives the signal first.
  4. Audioguru


    Dec 20, 2007
    The transformer steps up the voltage 7 times and since it is tuned with the capacitance of the piezo it steps up the voltage much more. Then the signal from the piezo is much higher than without the transformer so its range is much farther.
  5. PaulEE


    Dec 23, 2011
    If you can use different ultrasonic transducers, I would suggest you do so.

    I ordered a few of these awhile back and they were complete junk...maybe I didn't have enough voltage on them, but they wouldn't do a thing for me. (exact model, exact site)

    Let me know how it works out if you do get the things to function.
  6. hiya1432

    Thread Starter New Member

    Jan 30, 2012
    Would you recommend any other transducers that are above 50-60 kHz?