Piezoelectric Crystals: Constant Pressure & Electric Field

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In summary, according to the conversation, if a constant pressure is applied to a piezoelectric crystal, it will generate an electric field. However, this voltage may drop back to zero quickly due to imperfections in the crystal and the need to extract current to measure the voltage. It is also mentioned that ferroelectric materials have constant electric fields without the need for stress.
  • #1
ScienceNerd36
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If a constant pressure is kept on a piezoelectric crystal, will it continue to generate an electric field?
 
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  • #3
Actually, if you try this you will notice that the voltage drops back to zero quite quickly (seconds).
This is because the crystal is not a perfect insulator, and because you must extract some current to measure the voltage.
 
  • #4
Yeah, when you deform a piezoelectric crystal, a voltage builds up. But that means that there is going to be a force acting on any free charges hanging around, which will try to rearrange themselves to cancel the voltage. So after a while the crystal should be neutral again.
 
  • #5
Thanks for the help :)
 
  • #6
You may be interested in Ferroelectric materials too. These have constant electric fields wihout the need to apply a stress.
 
  • #7
You don't say. I'll be off to read up on them right now. Thanks :)
 

Related to Piezoelectric Crystals: Constant Pressure & Electric Field

1. What are piezoelectric crystals?

Piezoelectric crystals are a type of material that can generate an electric charge when placed under mechanical stress or pressure. They are also able to deform or change shape when exposed to an electric field.

2. How do piezoelectric crystals work?

Piezoelectric crystals have a unique molecular structure that allows them to convert mechanical energy into electrical energy. When pressure or stress is applied to the crystal, the positive and negative charges within the crystal are separated, creating an electric voltage. This process is known as the direct piezoelectric effect. Conversely, when an electric field is applied to the crystal, it causes a change in its shape or dimensions, known as the inverse piezoelectric effect.

3. What are some common applications of piezoelectric crystals?

Piezoelectric crystals have a wide range of applications, including in electronic devices such as sensors, transducers, and actuators. They are also used in medical imaging equipment, such as ultrasound machines, and in musical instruments, such as electric guitars. Additionally, piezoelectric crystals are used in energy harvesting technologies, where they can convert mechanical vibrations into electrical energy.

4. What is the relationship between constant pressure and electric field in piezoelectric crystals?

In piezoelectric crystals, a constant pressure or stress applied to the crystal will result in a constant electric field being generated. Similarly, a constant electric field applied to the crystal will cause a constant deformation or strain. This relationship is known as the piezoelectric effect and is the basis for the functionality of piezoelectric materials.

5. How do piezoelectric crystals differ from other types of crystals?

Piezoelectric crystals differ from other types of crystals in that they have a non-centrosymmetric crystal structure, meaning they do not have a center of symmetry. This unique structure allows them to exhibit the piezoelectric effect. In contrast, centrosymmetric crystals do not have this property and therefore cannot generate an electric charge under pressure or change shape under an electric field.

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