Piezoelectric materials within a vacuum

In summary: If there is no net output within the "creation"(0) atmosphere, and any slight elastic deformation shows itself in the form of an output, then a decrease in the pressure in which the material was created would produce some minute negative voltage output.
  • #1
jf2086
4
0
Would a piezoelectric crystal create a negative voltage if held within a vacuum? Perhaps it's my misunderstanding of the materials properties, but it seems that if there is zero net output within the "creation"(0) atmosphere, and any slight elastic deformation shows itself in the form of an output, then a decrease in the pressure in which the material was created would produce some minute negative voltage output.
Is there something I am overlooking?
Thank you for your consideration.
 
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  • #2
I guess an increase in the pressure would also be an applicable question.
 
  • #4
There is a duality between pressure and volume on one hand and stress and strain on the other.
Piezoelectricity is due to stress, not pressure. Hence changing the pressure will not induce a piezoelectric voltage, at least as long as the material is stress-free.
 
  • #5
But there would be stress in the crystal if it was under pressure no?
 
  • #6
Pressure, by definition, is the isotropic part of the stress tensor. If the crystal is homogeneous, there is no reason why pressure should go in hand with a non-isotropic stress.
 
  • #7
Thanks for your responses, gentlemen. Back to the drawing board!
 
  • #8
If a piezo only detects stress, and not pressure - then how can they make piezo absolute pressure gauges?

For example: http://www.mksinst.com/docs/UR/hps902ds.pdf [Broken]

In answer to my own question: they only expose a portion of the piezo crystal.
See http://cds.cern.ch/record/1046852/files/p65.pdf
 
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  • #9
UltrafastPED said:
If a piezo only detects stress, and not pressure - then how can they make piezo absolute pressure gauges?

Typically, you have a piezoelectric membrane which separates the area with pressure p from some vacuum chamber. It is then clear that a change of pressure will lead to stress, too. However, I understood that the OP was asking for what happens if you bring a piezoelectric crystal completely into vacuum.
 
  • #10
Indeed, I was curious if there would be any stress due to expansion resulting in negative voltage.
 

1. What are piezoelectric materials within a vacuum?

Piezoelectric materials are materials that can generate an electrical charge when subjected to mechanical stress or vibrations. When placed within a vacuum, these materials are not affected by air molecules and can exhibit a higher sensitivity to mechanical stimuli.

2. How do piezoelectric materials work within a vacuum?

Within a vacuum, piezoelectric materials experience minimal interference from external factors such as air resistance. When a mechanical force is applied to the material, the crystal structure within the material changes, causing a separation of positive and negative charges and creating an electrical potential.

3. What are the benefits of using piezoelectric materials within a vacuum?

Using piezoelectric materials within a vacuum can provide greater accuracy and sensitivity in measurements. It also eliminates the need for additional insulation or shielding from external factors, making the system simpler and more efficient.

4. Can piezoelectric materials within a vacuum be used in different applications?

Yes, piezoelectric materials within a vacuum have a wide range of applications. They are commonly used in sensors and transducers for measuring pressure, force, and acceleration. They can also be used in energy harvesting, sound amplification, and even in medical devices.

5. Are there any limitations to using piezoelectric materials within a vacuum?

One limitation of using piezoelectric materials within a vacuum is that the materials can be brittle and may not withstand high levels of stress or vibration. Additionally, the vacuum environment may not be suitable for all applications, and other factors such as temperature and humidity may still need to be considered.

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