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we used a RC circuit for measuring resonance frequency of a piezoelectric. And each time, we changed the frequency domain of the input. The impedance model, in terms of frequency, indicates that the peaks are shifted by varying the frequency of the applied action. Is it rational? Why? What is the best method for measuring piezoelectric resonance frequency?enter image description hereenter image description here

Fa Had
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  • Real piezoelectric devices can have more than one resonant frequency, depending on the shape. You could be seeing those, or there could be something wrong with your setup, or you could be driving it too hard and producing nonlinear effects which can shift the peak in the response. – uhoh Jan 02 '19 at 07:38
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    What is the best setup for measuring piezoelectric resonance frequency? – Fa Had Jan 02 '19 at 07:47
  • That might be a good question to search the internet, or to ask in Electronics SE. But search that site carefully first to see if there are answers there already that can help. Also the more details you can add to your question; how you are making electrical contact to the resonator, the shape of the piezo sample, maybe the type, etc... and maybe add a link to another answer there and explain why you need additional help, that will really improve your chances of getting a helpful answer. – uhoh Jan 02 '19 at 07:50
  • a quick check already turns up some possibly helpful posts: Finding the Resonance Frequency of a Piezo, Measuring the resonance point of a piezo ultrasonic transducer – uhoh Jan 02 '19 at 07:52
  • Thanks. I didn't find a suitable method for measuring resonance frequency of piezoelectric. – Fa Had Jan 02 '19 at 15:04
  • I think your question is too short and unclear for anyone to write a good answer for you. Is it possible to add a lot more information? A photo of your sample, or the setup you want to use, and more details of what equipment you plan to use for your measurement? If you have some data you don't understand, then it would be great to show that too, any way that you can. Just explaining what happens in the data in a few sentences is too hard for people to understand what you are really seeing. – uhoh Jan 02 '19 at 15:26
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    I use the above setup and measure voltage of piezo and resistor, then divided them. This impedance in terms of frequency is drawed. That peaks in graphs is shifted for three amplitude of input frequency. – Fa Had Jan 02 '19 at 16:52

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Your Amplitude-dependent Frequency Response Suggests Nonlinear Behavior.

The shift of resonant frequency with driving amplitude that you're seeing suggests (pretty strongly) that something in your system is nonlinear. It could be the piezo, its mounting/preloading hardware, your amplifier, your sensor, it's mounting, etc.

Note that some amplifiers (esp. those not specifically made to drive piezo actuators) may have trouble driving an effectively capacitive load (esp. below resonance), so there may be clipping/saturation/etc. in the power stage, even if a first look at the specs suggests otherwise. Measure the actual current through the piezo; a non-inductive power resistor will help if you lack something to measure current at high bandwidth. Hope this helps!

Catalyst
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