# Piezoeletric voltage generation calculation

1. Apr 29, 2009

### Nap04011

Hey,

I was wondering if someone could post or create/explain a simple piezoeletric problem in which a stress acts on a piezo material and creates a voltage.

I want to be able to understand how to caculate the voltage generated and current created.

Thanks for any help

2. Apr 30, 2009

### timmay

Try here, under applications.

3. Apr 30, 2009

### Nap04011

Thanks Timmay!

4. Apr 30, 2009

### Nap04011

Ok real quick so I followed throught it and understand

But when the start working the problem they say

d33= 25 pC/N

but when the work the problem the use 10.10^-10 for their e value to C???
shouldnt that e be 25pC/N????

5. May 1, 2009

### timmay

The first expression calculates the capacitance C of the sensor. Epsilon is the electrical permittivity of the material, A is the area, t thickness. C'' is the capacitance per unit area.

$$C^{''} = \frac {\epsilon} {t}$$

$$C = \frac {\epsilon A} {t}$$

$$C = 10E^{-10}\times\frac {1E^{-2}*1E^{-2}} {100E^{-6}}$$

$$C = 100 pF$$

To calculate the charge generated under a load of 10 N:

$$Q = 25 pC/N \times 10 N = 250 pC$$

Knowing the relationship between voltage, charge and capacitance:

$$V = \frac {Q} {C}$$

$$V = \frac {250 pC} {100 pF}$$

$$V = 2.5 V$$

Make a bit more sense?

Last edited: May 1, 2009
6. Dec 2, 2010

### kaelibw

Where exactly did you find these calculations. Im currently in a research team in highschool working on developing piezoelectric nanofibers.