High frequencies and capacitor plates

Click For Summary

Homework Help Overview

The discussion revolves around the behavior of capacitors at high frequencies, specifically whether current flows through the capacitor plates or if it is related to charge storage and discharge during AC current reversal.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the nature of current flow in capacitors, questioning whether current literally passes through the plates or if it is a matter of charge storage and return to the source. Some seek clarification on the implications of current direction changes in AC circuits.

Discussion Status

Participants have provided insights regarding the behavior of capacitors in AC circuits, noting that current does not flow through the dielectric and discussing the implications of current direction changes. There is an ongoing exploration of the concepts without a definitive consensus.

Contextual Notes

There is some ambiguity in the original poster's question regarding the mechanics of charge return and current flow, which has led to further clarification requests and interpretations among participants.

jeff1evesque
Messages
312
Reaction score
0
Hello,

I was wondering at high frequencies, does current literally go through the capacitor plates; from one side to the other? Or is it simply due to charges being stored on the plates, that once the polarity of the circuit has changed, the charges on the plate that has been stored from it's source return back to it's source?

Jeffrey Levesque
 
Physics news on Phys.org


Nope, the current does not "literally" go through the capacitor plates.
 


It is stored due to the charges but I am not sure what you mean by the last part of your question.
 


rock.freak667 said:
It is stored due to the charges but I am not sure what you mean by the last part of your question.

When the current is going a particular direction, the plates charge in a respective fashion. When the current reverses due to the nature of the AC circuitry, does the current go through from one plate to another, or when the current reverses, the stored charges from the plate simply returns to it's source- thus no current went through (between) the capacitor plates?

Thanks,


JL
 


If the current changes direction, then the capacitor will start to discharge.
That is why you can use a capacitor to convert AC to DC
 


More specifically, a capacitor is used to filter the DC-output of an AC rectifier. It filters out the current that comes out of the rectifier, since there's no such thing as an ideal rectifier.

Now to your question, when the current reverses in AC, it will flow into the negative plate of the capacitor. In order to balance out that change in charge, the other plate will then discharge. If I'm interpreting your question correctly, then the answer is no; current does not flow through the dielectric. Current only flows straight through a capacitor when dielectric breakdown occurs.
 

Similar threads

Replies
11
Views
3K
Replies
11
Views
4K
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 26 ·
Replies
26
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
20
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K