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I assume it will be something along the lines of feeding it a sine wave via a resistor and measuring the signal across the resistor as the frequency changes. Does this sound viable? Also, on resonance does the current maximize or minimize? A complication is that it presents as a capacitor. [Also, I have no way of measuring the sound output]

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  • \$\begingroup\$ Hi, did you solve this? thx \$\endgroup\$
    – johny why
    Jan 23, 2015 at 2:19

2 Answers 2

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Another approach (assuming this is a beeper type of thingie) would be to whip out your calipers etc. and measure the dimensions of the resonant cavity.

No way at all to measure the sound level? Microphone and sound card? If you have a signal generator with noise out, that could do it (FFT in software).

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  • \$\begingroup\$ It is in the hundreds of kHz, and I cannot afford to destroy it \$\endgroup\$
    – user32885
    Feb 26, 2014 at 8:50
  • \$\begingroup\$ If you have enough information about the transducer you may be able to measure it (physically) and apply formulas. tinyurl.com/k34bpb2 \$\endgroup\$ Feb 26, 2014 at 13:14
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Ideally you'd use an oscilloscope and look at the voltage across the piezo device reach a peak of amplitude. Feed it from a ~1kohm resistor and a signal generator and adjust the frequency until you see a maximum waveform on the o-scope.

Trying to use a standard multi-meter will probably be fruitless because, at the frequencies the piezo is resonant, the meter will not measure much on AC and it is an AC measurement that is needed.

If you supply a link to the exact part I might be able to provide more info.

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  • \$\begingroup\$ Unfortunately I don't know the part - I am trying to find out what it is. No markings on it as far as I can tell. \$\endgroup\$
    – user32885
    Feb 13, 2014 at 12:23

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