Can Continuous Pressure on Piezoelectric Crystals Generate a Constant Voltage?

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Discussion Overview

The discussion revolves around whether continuous pressure on piezoelectric crystals can generate a continuous voltage. Participants explore the implications of applying constant versus variable pressure on the crystals and the associated energy considerations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question if continuous pressure on a piezoelectric material can produce a continuous potential, suggesting that energy production without conversion may violate the law of conservation of energy.
  • Others argue that maintaining a constant potential does not involve energy consumption or production, and that work is only done when charges move through a potential.
  • A participant mentions that after applying constant pressure, a potential difference will arise, but current will cease once equilibrium is reached, indicating no useful work can be performed thereafter.
  • Another participant introduces the idea that variable pressure, such as sinusoidal application, would allow for alternating current to flow continuously.
  • One participant references a specific example from Wikipedia, noting that a 2 kN force could generate a potential of 12,500 V, inquiring about the usability and energy conversion efficiency of this scenario.

Areas of Agreement / Disagreement

Participants express differing views on the ability of continuous pressure to generate a continuous voltage, with some asserting it cannot while others suggest that the nature of the pressure application (constant vs. variable) significantly affects the outcome. The discussion remains unresolved regarding the implications of these differing perspectives.

Contextual Notes

Participants reference the law of conservation of energy and the behavior of piezoelectric materials under different conditions, but there are no settled definitions or consensus on the mechanics involved in energy conversion efficiency or the specific conditions under which voltage is generated.

Who May Find This Useful

This discussion may be of interest to those studying piezoelectric materials, energy conversion processes, or the principles of electrical potential in response to mechanical stress.

neerav
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I wanted to ask if a continuous pressure on a piezoelectric produce a continuous potential or not??if not why??
 
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neerav said:
I wanted to ask if a continuous pressure on a piezoelectric produce a continuous potential or not??if not why??
What would be your guess, and why?
 
well i would guess that it should not give a potential under constant load as energy is getting produced without any actual conversion hence it voilates law of conservation of energy
but could not find anything to support my guess
 
There is no consumption or production of energy, in maintaining of a constant potential. It is only when you change the potential or move charges through this potential that work is done. That is not the case here.

Anyway, you are saying that piezoelectricity itself should not be possible - not that the peizoelectric voltage be a continuous function of the applied stress. Neither of the above is true, in the general case. For the latter, think "first order phase transitions"
 
oh sorry i forgot to say i intended to use the potential and hence change it
 
neerav said:
oh sorry i forgot to say i intended to use the potential and hence change it

After you applied a constant pressure to the piezoelectric crystal there will be a potential difference between two crystal surfaces. If you connect these surfaces by a wire, the electrons will flow from one surface to another. The current will stop after enough charge is transferred to compensate the original potential difference. There will be no current in the equilibrium, so no useful work can be performed after the equilibrium has been reached.

The situation is different if the pressure applied to the crystal is variable, e.g., sinusoidal. Then an alternating current will flow through the circuit as long as the pressure is applied.

Eugene.
 
thanks for the explanation but i have read on wikipedia if properly applied a 2kn force can create a potential of 12500V is it usable and what is its energy conversion efficiency
crystal is 1cm cube
 
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