Piezoelectric Sensors Change with Frequency

Thread Starter

rperea

Joined Apr 7, 2009
15
I am trying to explain why the voltage increases when the frequency increases. I am testing a piezoplate at 1Hz and 2Hz, 10 cycles and a force of 30N. I collect the voltage difference. The votlage increases with frequency.

The equations for piezoelectricity are:

ε = SE * σ – da 33* Efield
Electric Displacement = d33a * σ + (Permitivity) * Efield {Eq. 4}


So.....what parameter depends on frequency? Is it the permitivity?
 

beenthere

Joined Apr 20, 2004
15,819
Probably the piezo element is rate sensitive. Shake it faster and get a higher output for a given force applied.

There is probably some resonant point where the mechanical energy is coupled most efficiently - a simple experiment should should a peak output at that frequency.
 
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Thread Starter

rperea

Joined Apr 7, 2009
15
Thanks for the reply. What do you mean rate senstitive? I knoe the higher the frequency the higher the voltage I will get....now I am trying to understand this concept in the constitutive equations.....where thats the frequency play?
 

BillB3857

Joined Feb 28, 2009
2,570
Assuming you are using a uniform level of mechanical excitation, and plot the distance of excursion vs time, you will see that the rate of change in position is faster at higher frequencies.
 

Thread Starter

rperea

Joined Apr 7, 2009
15
Again, is permitivity a function of frequency?
Where does the frequency rate play the role in the consitutive equations?

Sorry to be so confusing.
 
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