Compression on Piezoelectric crstals

Click For Summary

Discussion Overview

The discussion revolves around the ability of piezoelectric crystals to generate electricity from compression forces. Participants explore whether continuous compression can yield a DC voltage source, the behavior of the crystals under varying pressures, and the practical implications for energy generation in projects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants question if piezoelectric crystals can produce electricity solely from compression, and whether this can yield a DC voltage source.
  • There is a suggestion that piezoelectric crystals behave like capacitors, storing voltage that may eventually leak away.
  • One participant notes that while some crystals can generate high voltages, others produce very low voltages, indicating variability in performance.
  • Concerns are raised about the inherently low power output of piezoelectric devices, suggesting that many devices may be needed to achieve significant current.
  • Participants discuss the impact of increasing surface area and mechanical pressure on voltage generation, noting that responses may not be linear.
  • It is mentioned that static pressure results in static voltage, which cannot do much work as it quickly equalizes with the circuit, contrasting with the behavior of batteries.
  • Some argue that continuous power extraction from piezoelectric devices requires varying pressure, such as through vibration.

Areas of Agreement / Disagreement

Participants express differing views on the effectiveness of compression alone for generating electricity and the nature of voltage produced by piezoelectric crystals. There is no consensus on the best methods for maximizing output or the implications of static versus dynamic pressure.

Contextual Notes

Limitations include the dependence on specific definitions of pressure and voltage output, as well as the unresolved nature of how various factors influence the performance of piezoelectric devices.

SmritiB
Messages
17
Reaction score
0
Can piezoelectric crystals produce electricity from compression only ? When continuous compression and tensile forces on them generate AC voltage source, can only compression force give me a DC voltage source ? Is there a chance that the crystal will initially act as a Voltage source but soon re-adjust itself to get its acquired polarity neutralized ? If so, how long typically can the polarity last ? And I would also be glad if i could get some data for my project. specifically: 1.What is the minimum pressure required for any piezoelectric crystal to generate electricity ?
2. How much Volts can i expect from that pressure?
 
Physics news on Phys.org
SmritiB said:
Can piezoelectric crystals produce electricity from compression only ? When continuous compression and tensile forces on them generate AC voltage source, can only compression force give me a DC voltage source ? Is there a chance that the crystal will initially act as a Voltage source but soon re-adjust itself to get its acquired polarity neutralized ? If so, how long typically can the polarity last ? And I would also be glad if i could get some data for my project. specifically: 1.What is the minimum pressure required for any piezoelectric crystal to generate electricity ?
2. How much Volts can i expect from that pressure?
No one has answered you. I think the piezo crystal acts like a small capacitor, so the voltage which is developed is stored across the two surfaces, and eventually it will leak away. The available energy is stored in the capacitor, 0.5 CV^2. Some crystals can give high voltages, sufficient to spark, as with a gas lighter, and others are used for microphones, where the faintest sound still generates a few microvolts. Quartz is used for stable piezo resonators for electronics. I don't think there is any one-way action, and tension, compression and bending will all generate a voltage.
 
  • Like
Likes   Reactions: SmritiB
tech99 said:
No one has answered you. I think the piezo crystal acts like a small capacitor, so the voltage which is developed is stored across the two surfaces, and eventually it will leak away. The available energy is stored in the capacitor, 0.5 CV^2. Some crystals can give high voltages, sufficient to spark, as with a gas lighter, and others are used for microphones, where the faintest sound still generates a few microvolts. Quartz is used for stable piezo resonators for electronics. I don't think there is any one-way action, and tension, compression and bending will all generate a voltage.

Thankyou for your idea.
 
I'm too lazy to do it right now, but boy that Wikipedia chapter needs some editing. Some dude essentially used it for self-promotion.
 
anorlunda said:
Sorry, piezioelectric devices are inherently low power. To boost 1 microamp to 1 amp, you need a million piezioelectric devices in parallel.

See

http://en.m.wikipedia.org/wiki/Energy_harvesting#Piezoelectric[/QUOTE0
Your analysis was for millions of crystals of what size ?
What if I increase the surface area or the mechanical pressure on it ? are these methods effective in boosting the generated voltage ?
 
All those things of course increase the output (up to a point of course, you can't just arbitrarily raise the pressure on a piezo and expect linear response all the way).

The key constraint however is that static pressure creates static voltage, but that static voltage, kinda like a charged capacitor, can't do much work because it quickly becomes equalized with the rest of your circuit. Piezos don't work like batteries which can continuously push electrons. After all, piezos don't actually conduct electricity, so you can't have a circuit like with abattery.
The moment you connect something to a piezo, just like the moment you connect something to a charged capacitor, the piezo will lose voltage differential.

So, the only way to continuously extract power from a piezo is through varying pressure, I.e. vibration.
 
Last edited:
  • Like
Likes   Reactions: SmritiB
rumborak said:
All those things of course increase the output (up to a point of course, you can't just arbitrarily raise the pressure on a piezo and expect linear response all the way).

The key constraint however is that static pressure creates static voltage, but that static voltage, kinda like a charged capacitor, can't do much work because it quickly becomes equalized with the rest of your circuit. Piezos don't work like batteries which can continuously push electrons. After all, piezos don't actually conduct electricity, so you can't have a circuit like with abattery.
The moment you connect something to a piezo, just like the moment you connect something to a charged capacitor, the piezo will lose voltage differential.

So, the only way to continuously extract power from a piezo is through varying pressure, I.e. vibration.

I see, Thanks a lot.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
5K
  • · Replies 5 ·
Replies
5
Views
8K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
7
Views
9K
  • · Replies 50 ·
2
Replies
50
Views
13K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 5 ·
Replies
5
Views
8K