I have several piezoelectric stacks that I am trying to get to shake/oscillate. An example of what I mean by piezoelectric stack is something like Thorlabs PA3CEW.

The drive voltage is specified as 0 - 100 V. I am wondering, in order to create the best-designed "shaker", should one drive the piezo with either:

  • Square wave moving between 0 Vdc and 100 Vdc
  • Square wave moving between -100 Vdc and 100 Vdc
  • AC sine wave of 100 Vrms

Thank you in advance for your guidance! I am new to working with piezoelectric devices.

  • 1
    \$\begingroup\$ A square wave is not DC. \$\endgroup\$
    – Hearth
    Jul 8 '19 at 21:25
  • 1
    \$\begingroup\$ According to the spec sheet: Reverse biasing the device may cause mechanical failure. \$\endgroup\$
    – Mattman944
    Jul 8 '19 at 21:39
  • \$\begingroup\$ You do realize that the displacement is minuscule, what are you shaking? \$\endgroup\$
    – Mattman944
    Jul 8 '19 at 21:41
  • \$\begingroup\$ The same as needed mechanical movement response. \$\endgroup\$ Jul 8 '19 at 22:12
  • \$\begingroup\$ A square wave switching between 0V and 100V is DC. It's pulsating DC. \$\endgroup\$
    – James
    Jul 9 '19 at 8:49

A sine wave is recommended because it consists of only one frequency. A square wave consists of the fundamental frequency plus all odd harmonics. When the piezoelectric stack is excited with a sine wave, it will vibrate only at that frequency. When the stack is excited with a square wave, it will vibrate at the fundamental frequency and at all of the harmonics. Some of those harmonics may be near mechanical resonant frequencies of the stack and can cause excessive and possibly damaging vibrations. Also, with all of those frequencies present, it can be difficult to interpret the results of the stack vibrating whatever is attached to your shaker.

  • \$\begingroup\$ What if the sine wave has a positive offset @Barry? For example, I realized from Mattman944's comment above, that I cannot apply a negative voltage. Will the harmonics still exist if I have a 100 volt peak-peak sine wave, offset 50 Vdc? \$\endgroup\$ Jul 9 '19 at 16:23
  • \$\begingroup\$ @IntrastellarExplorer there is no harmonic content in a DC offset, however, you can have harmonic distortion with a pure single frequency input if the system itself is non-linear, which to an extent it will be. And the DC bias may put you further into nonlinearity. \$\endgroup\$ Jul 9 '19 at 18:49

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