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I was researching how the transducer works for an ultrasound machine.What I learned was from a piezocrystal (quartz) the applied mechanical stress can produce an alternating electric field (from the potential difference of the mostly positive and mostly negative ends of the lattice) and therefore an alternating electric current.

To me this sounds a like a change in both magnetic fields induces current like Faraday's law.

If anyone could maybe confirm, deny, and elaborate on this would be greatly appreciated.

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A piezoelectric transducer produces an alternating voltage only when it is being flexed repetitively. For a static applied stress, it produces a static voltage. Similarly, if a DC voltage is applied to the piezoelectric crystal, it bends and remains so for as long as the voltage is maintained. If an alternating voltage is applied to it, it will flex back and forth. This happens because flexing the piezoelectric crystal alters the bulk charge distribution within it, and vice versa.

This characteristic is unrelated to Faraday's law.

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  • $\begingroup$ @amerepigeon, will you vote to accept? $\endgroup$
    – niels nielsen
    Commented Apr 7, 2018 at 19:51
  • $\begingroup$ "Flexing" is for bilayer transducers, with oppositely polarized layers. Or for tubes. For things like quartz, it is pressure and strain. $\endgroup$
    – user137289
    Commented Apr 9, 2018 at 20:29
  • $\begingroup$ amerpigeon, see Pieter's comments above. -NN $\endgroup$
    – niels nielsen
    Commented Apr 9, 2018 at 22:00

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