Capacitors don't require a dielectric material they?

Click For Summary

Discussion Overview

The discussion centers on the role of dielectric materials in capacitors, specifically questioning whether capacitors can function without them. Participants explore the distinctions between dielectric materials and non-dielectric insulators, as well as the implications for electric field behavior within and outside the capacitor.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant suggests that dielectric materials are not strictly necessary for capacitors, arguing that the relative permittivity constant can be derived from non-dielectric insulators.
  • Another participant questions the definition of "non-dielectric insulator" and seeks clarification on the term and its implications for electric fields.
  • A participant expresses uncertainty about the distinction between dielectrics and insulators, proposing a spectrum of materials based on polarizability.
  • It is noted that a capacitor can theoretically have a vacuum between its plates, with air serving as a close approximation under certain conditions.
  • One participant challenges the initial claim, emphasizing that all materials can be polarized to some extent and questioning the existence of a true "non-dielectric." They explain that polarization affects capacitance by reducing the electric field between capacitor plates.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the necessity of dielectric materials in capacitors, with multiple competing views and definitions of terms remaining unresolved.

Contextual Notes

There are limitations in the discussion regarding the definitions of dielectric and non-dielectric materials, as well as the implications of polarizability on electric fields. The concept of "non-dielectric" is not widely recognized or defined in the context provided.

iScience
Messages
466
Reaction score
5
capacitors don't require a "dielectric" material they?

whenever i hear about capacitors, i hear about the 'dielectric' material, but a dielectric material as opposed to a non-dielectric insulator just means that the material is polarizable. but polarizability only affects the field strength within the insulating material it doesn't really affect the externally applied E-field coming out the other end. what does affect the E-field coming out the other end is the relative permitivity constant, which can be obtained from any non-dielectric insulator right?
 
Physics news on Phys.org
What is a "non-dielectric insulator"? Do you have an example?
And what is the "electric field coming out the other end"? The other end of what?
 
can't think of any examples, I'm actually new to the whole distinction between dielectrics and insulators.. so i thought that insulating materials consisted of a spectrum, with one end of the spectrum being non-dielectric (non-polarizable) materials, and dielectric (or, easily polarizable) materials on the other end of the spectrum. is this view incorrect? if so can you give me a clearer picture of the distinction/relationship between dielectrics and insulators?

what is the "electric field coming out the other end"? The other end of what?

referring to the electric field going into the insulator material and coming out of it on the opposite end from which it entered
 
You can have a capacitor with vacuum between the plates, in principle. Air is a fairly good approximation to a vacuum in this context, for relatively low electric fields inside the capacitor.
 
I still think you are miss-understanding something.
Some materials can be polarized more than others, this is true.
And is measured by the dielectric constant (or by permitivity). What would you expect the permitivity of a "non-dielectric" to be?

You may consider vacuum as an insulator which is not polarizable (see Jtbell's post) but I don't see the use.
Have you seen the term "non-dielectric" in a book or paper?
All materials made from atoms can be polarised in electric fields because the atoms can be.
If the polarization is small they have a small dielectric constant but I don't think they are called "non-dielectrics". Air has a pretty small dielectric constant, almost close to 1, but it's still a dielectric, isn't it?

The effect you are talking about in capacitors is produced by polarisation of the material between the plates. The polarization field reduces the field between the plates and so the voltage. The effect is increased capacitance.
A material without polarization (assuming it exist) will do nothing for this.
 

Similar threads

Undergrad Why is a Dielectric slab ejected from the capacitor when energized?
  • · Replies 10 ·
Replies
10
Views
3K
Graduate How to define ##\nabla \cdot D ## at the interface between dielectrics
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Is capacitor energy the electrostatic energy of the whole system?
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad How Do Dielectrics Influence Electric Flux Density in Electromagnetic Theory?
  • · Replies 5 ·
Replies
5
Views
2K
Graduate Understanding Dielectric Materials: E Field and Coulomb Force Explained
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Faraday induction in constant B field, with non-conduction wires
  • · Replies 2 ·
Replies
2
Views
2K
High School Is dielectric necessary in capacitors?
  • · Replies 18 ·
Replies
18
Views
2K
Undergrad Help clarifying capacitors, dielectrics, E field, potential
  • · Replies 2 ·
Replies
2
Views
2K
Graduate A Capacitor With A Dielectric But Also Free Space in Between
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Build a Capacitor in 30 minutes
  • · Replies 2 ·
Replies
2
Views
2K