Dielectric Polarization and leakage effects?

In summary, the conversation discusses the relationship between dielectric polarization and leakage current in a capacitor. The individual asking the question wonders if polarizing a lossy dielectric would decrease the leakage current. The response explains that the polarization of the dielectric does not affect leakage and that all dielectrics polarize in the presence of an external electric field, but some have more loss than others. The conversation also mentions that mineral impurities or contaminants can cause leakage and that there have been cases of capacitors blowing up due to dielectric breakdown.
  • #1
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When the dielectric in a capacitor polarizes does it effect the leakage current through the dielectric?

Just wondering, if you had a capacitor with a lossy dielectric and you were able to polarize the dielectric would the leakage current drop?

Can anyone give me any links for further reading on this subject?
 
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  • #2
My understanding is the polarization of the dielectric has nothing to do with leakage of the dielectric. dielectric is material that the outer shell electrons are being held tight to the nucleus and are not free to move. Under the E field, the nucleus move a little to the -ve side and the electrons move a little to the +ve side of the E field and form a dipole. that has nothing to do with whether it has any leakage or not.

ALL Dielectric polarize in the presence of external E but some has more loss( leakage) some has less.

Electromagnetic textbook do talk about this. But they are usually not very good in explaining this.
 
  • #3
If there are mineral impurities that conduct electricity, or contaminants, it could cause leakage and/or reduce the dielectric breakdown level of the fluid being used as the dielectric.

I wonder if why some capacitors blow up like balloons is because of dielectric breakdown causing some gas to be formed in the capacitor causing it to blow up and expand.. this is just pure speculation and not proven. There were some computers out there that had to be recalled due to blown up capacitors.
 

1. What is dielectric polarization?

Dielectric polarization is a phenomenon that occurs when an external electric field is applied to a dielectric material. This causes the electric dipoles in the material to align with the field, resulting in a net dipole moment within the material.

2. How does dielectric polarization affect the behavior of materials?

The presence of dielectric polarization can significantly alter the electrical properties of materials. It can increase the capacitance of a material, making it better at storing charge, and it can also reduce the electric field within the material, making it more resistant to breakdown.

3. What is the difference between electronic and ionic polarization?

Electronic polarization occurs when the electrons in an atom or molecule shift in response to an electric field, while ionic polarization occurs when the ions within a material move in response to an electric field. Electronic polarization is typically faster and stronger than ionic polarization.

4. What is dielectric leakage?

Dielectric leakage, also known as dielectric breakdown, refers to the phenomenon where a dielectric material cannot withstand a high enough electric field and breaks down, resulting in a flow of current. This can be damaging to electronic devices and can also cause safety hazards.

5. How can dielectric polarization and leakage be controlled?

Dielectric polarization and leakage can be controlled by choosing the right dielectric material for a specific application. Materials with high dielectric strength and low dielectric constant are less prone to polarization and leakage. Additionally, reducing the thickness of the dielectric layer can also help minimize these effects.

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