Can an open circuit voltage field charge a capacitor?

[Dale]

My response to a claim my post is ambiguous because some people might think shorting is grounding, is my claim that there should is no need to define electrical ‘short’ to an audience with a knowledge of physics 101.

The standard term "short" refers specifically to an unintended conduction path between two parts of an electrical circuit. There is no circuit in the context of "shorting the voltage between capacitors". So although you are using a standard term you are using it in a very non-standard context and it is perfectly reasonable for someone to ask you to define it.

Your response to Defennder that it is a standard term that you should not have to define is not helpful, and it is not polite to imply (I hope unintentionally) that someone who is trying to help you lacks even a freshman-level knowledge of physics.

I am trying to reconcile the difference between shorting a capacitor and shorting the voltage between capacitors. I suppose I should first ask about ‘sheets of charge’.

Let me try to define the terms as I understand the question and you can agree or clarify:

Shorting a capacitor is placing a conductor (wire) such that it touches both plates.

Shorting the voltage between capacitors is placing a conductor (plate) such that it does not touch either capacitor plate, but that it is in located in the region between the capacitor plates.

If that is the question then the differences are:
1) there is no charge separation in the first case
2) there is no E-field anywhere in the first case

Both Styrofoam and a vacuum are insulators that can contain a voltage gradient.

Be careful in assigning material properties to vacuum, but yes a voltage gradient is an E-field, which can exist in a vacuum.

Shorting any portion of a voltage gradient reduces only that portion of the voltage gradient to zero. Therefore, shorting a portion of a voltage gradient within a vacuum reduces only that portion of the vacuum voltage gradient to zero. When a portion of a voltage gradient within a vacuum is shorted, there is no release or flow of point charges from the vacuum to the conductor.

Correct.

In the original problem, the two isolated insulators could have been composed of vacuum dielectric material; the area between the insulators could also have been composed of vacuum dielectric material.

Again, be careful in assigning material properties to vacuum, here if you want your charges to "stay put" then you will have to use a charged insulator not vacuum. Otherwise they will simply accelerate towards each other.

 

[Dale]

I was hoping to keep this short and simple. Basically this is a disagreement over whether or not a voltage gradient must be nearby point charges.

It doesn't have to be a point charge (it could be any charge distribution), but yes, there must be some charge in order to get an E-field. I do not think this has ever been a point of disagreement.

A voltage gradient will always accelerate a point charge within the voltage gradient, away from the voltage gradient.

Yes, F = q E. For a negative q you get F in the direction opposite the E-field, and if there are no other forces acting on the charge F = m a.

Again, I feel like we are not getting to your core confusion. I haven't found any gross misunderstandings in your last couple of posts. Does your question have something to do with energy conservation? Or conservation of charge? Or the definition of capacitance? Please try to distill it down to your fundamental question. I think we are "not seeing the forest for the trees".

 

[pzlded]

Hi Defennder

I appreciate the help you have been providing. I wish to apologize for making the following comment.

My response to a claim my post is ambiguous because some people might think shorting is grounding, is my claim that there should is no need to define electrical ‘short’ to an audience with a knowledge of physics 101.

I used ‘shorting’ to mean the short-circuit condition used in network theory to describe a general condition of zero voltage. For example, the term short-circuit admittance (or impedance) is used to describe a network condition in which certain terminals have had their voltage reduced to zero, for the purpose of analysis.

I realize that you were presenting thoughtful responses to my posts. Albeit I sometimes fail, I’ll make an extra effort to keep my posts within this forum professional. Please realize that this is not easy. It is difficult for me to present complex ideas as if they were intuitively simple. In this case, I forgot that both the words used to present the ideas and the ideas are not intuitively simple.

 

[Defennder]

Hi pzlded,

I guess it's normal for posters to get carried away at times just as I might have responded to your post more harshly than I intended to. It's something we all have to live and deal with I suppose.

In any case, I'm curious about the origin of the questions you're asking. Are they from some textbook you are reading or some lab assignment? I think it'll help a lot if you would be kind enough to tell us where these questions are from, that way it can help provide some perspective and context for us to answer your questions in a more productive manner.

 

[pzlded]

Hi Defennder

In any case, I'm curious about the origin of the questions you're asking. Are they from some textbook you are reading or some lab assignment? I think it'll help a lot if you would be kind enough to tell us where these questions are from, that way it can help provide some perspective and context for us to answer your questions in a more productive manner.

I’ve prepared a PowerPoint sideshow that is definitely 'draft' to provide an overview of my radical ideas related to point charge physics. The sideshow can be downloaded from the following website:

http://mysite.verizon.net/vzezz9ms/

Let me know if you have any problems accessing this material. Please be careful about referencing the material in the sideshow: The material within this sideshow is not peer reviewed and many people feel that there is no need to create an alternative to traditional theory.