Can the Dielectric Permittivity of a Material Be Altered?

[sophiecentaur]

in other words i think one can achieve much greater capacitance change

I expect you really mean "I would hope that" and not "I think".

That stuff is interesting but it's not the real unobtanium of your dreams because it involves radiating the substance with UV. The actual levels needed are not specified and, aamof, the wording does not actually imply that a Variable C is produced, rather that the C is "tuneable", which could be a one-off, setting operation - after which the C is left at the wanted value. I have never said you can't get a variable C of some sort. I have just been very skeptical about the practicality of using it as a Power Amplifier / Switcher component.

 

[Simon Bridge]

Well a few tens of pF chnage for my application is really too small

... not paying attention: no amount of variable capacitance would be useful for the application you have described so far.

It could just be poorly described of course.

 

[Mr.Bomzh]

Ok , I see siagreeing impinions again so let me make a summary of what I think I have learned in the process and also from you Simon and Sophie:)

1) A " stand alone" or out of circuit capacitor that is charged to some given value , upon dielectric consatnt change will either decrease or increase the PD across the plates, because the charge has no where to flow so if the field between the plates is varied the charges will try to conserve the field and so voltage will vary.

2) A capacitor in a circuit will produce charge flow towards it or away from it , if the dielectric constant will be changed because for example if the consatnt decreases the field between the plates gets stronger and less charge is needed to sustain it and because alike charges repel so some " unnecessary" charge flows away frm the capacitor, the opposite happens if the dielectric constant of the dielectric between the plates is increased , now the field weakens due to the material blocking some if it so more charge is needed to set up the field in it's previous condition so charge flows towards te capacitor and capacitance increases as more charge now resides on the same area of the same plate size.

3) the last one , the tricky part, changing te dielectric consant involves doing work on the capacitor which then in a circuit situation manifests itself as the change in electric field between the plates which then in turn manifest as charge flow towards or away from the capacitor which can be used to do work through induction or other ways like putting a bulb in series or etc.
if the capacitor stands out of a circuit then doing work on the dielectric constant would manifest itself purely as voltage increase decrease across the plates or PD change.

Are my summary assumptions correct?

 

[sophiecentaur]

I cannot divine what your "summary conclusions' are, I'm afraid.
If you do a proper course on Electricity you will not find the sort of description you are giving, applied to any simple circuit function. It is not precise or quantitative. If you want to be understood (and understand) about this then you have to approach the subject in the proper (conventional) way. In amongst those three paragraphs, above, there are some glimmerings of meaning but it fails because you are determined to think it and present it 'your way'.
I can't imagine you would give such an arm waving description of a bit of arithmetic or algebra and expect anyone to pay you any attention.

 

[Mr.Bomzh]

Oh god damn , I guess it has to do with the way I explain stuff.

Ok Ill try simpler, Change the dielectric constant of a dielectric between the plates of a capacitor and you get a change in capacitance when the cap is in a circuit or you get a change in voltage if the cap is charged and then disconnected from a circuit, because as we concluded and it also seems logic to me that upon changing capacitance if the charge has a path to go then it will if it doesn't then the PD across the plates will change because the charge has nowhere to go so something must give.

Ok I agree there is a oficially accepted way of things we know and then there are opinions but everyone as one , I mean we all see the world around us in some very personal way , even physics , one understand it by water analogies other people by different things etc.Maybe I'm just excusing myself anyway I;m sarting to get really dissappointed about this whole thing, not because of you , you've guys bee a great helf , I'm rather angry that the stupid physics :D doesn't work out the way it needs to.. :D:D
I still kinda get that the damn charge must flow if one does the things mentioned above from a capacitor if it is connected to a proper circuit, ground, +ve etc and it can't flow if the cap is alone , I hope that thing is clear.

 

[sophiecentaur]

"Personal Opinions" have a habit of causing circuits to burn out and bridges to collapse. If you want to deal with these sorts of problems from a personal and subjective point of view then you are unlikely to get far. You can see the world any way you want to but if you want to affect it and make it work as you want then you need to learn the way it works.
The few equations that apply to basic electrical circuits are all you need here. If you aren't prepared to use them and believe what they tell you then I can't see you making much progress, I'm afraid. You just have to talk the right language if you want to be understood. That's life, I'm afraid.

 

[Mr.Bomzh]

Yes true , even though many people see one thing and they go it and yet they each have a different take on it and how they get there.even though there are things which are true for everyone no matter their angle or opinion like mathematics.
well anyway was it at least right the thing I said it my last post?

 

[sophiecentaur]

I really can't tell.

 

[Mr.Bomzh]

Yes true , even though many people see one thing and they go it and yet they each have a different take on it and how they get there.even though there are things which are true for everyone no matter their angle or opinion like mathematics.
well anyway was it at least right the thing I said it my last post?
Hmm I don't know what to think, at the end of this thread I almoust felt I got it and you were suggesting that also , now 2+2 ain't 4 again.

I guess I'll stick to this what you said

The charge changes as the Capacitance changes.

 

[sophiecentaur]

Forget the words.
Q = CV is the equation. It says it all and you can't have "a different take on" Q=CV any more than you can have a different take on how much money you have in your pocket.
If you hold V constant then obviously Q is proportional to C. If charge cannot flow, then V is proportional to Q. If you . . . . . . and all the other possible combinations.
Isn't the whole point of using formula that it avoids endless chat, putting things one way and then another? If you have too much of a problem with interpret Q=CV then I suggest you drop the whole thing. You can't expect to make new inventions work without some calculations.
See - I'm getting grumpy now. Sorry.

 

[Mr.Bomzh]

ok I think I understand, thank you. from the bright side I hope I just made your tolerance level before you reach grumpiness a lot higher. :D

 

[sophiecentaur]

It's like water on stone - you get to me eventually.

wibble wibble wibble

Are you familiar with the 'beans' sequence in Blackadder?

 

[Mr.Bomzh]

I just looked up the show , sitcom apparently , well no I was not aware of this, but I greatly appreciate and personally like many of Rowan Atkinsons works, Mr. Bean would be probably the greatest , also some of his tv fun stuff before the Mr.Bean era.
I just put Blackadder on my downloads , will check it out, thanks.
So what the sequence is about ?

I hope it's not about those kinda unpleasant words written in the premise : http://en.wikipedia.org/wiki/Blackadder

:D

 

[sophiecentaur]

Ah. Different TV culture.
Lord Blackadder is trying to use a discussion about beans to teach his manservant Baldrick, arithmetic. Baldrick is only interested in beans as something to eat. You have been, similarly ignoring the Maths in favour of a chat and some arm waving. He is constantly criticising poor Baldrick in every episode. Baldrick always tries his best.

 

[Mr.Bomzh]

Oh I see, well I'm not good at maths so whenever one doesn't speak about QM or some other math heavy things , I try to talk in language which is called common english :D
I no doubt agree that math would be better but I think one can undersatnd caps without it too, their not that cpmplocated.I do realize that this statement probably made you loose some of your hair at the very instant you finished reading it. :D
i promise if i ever will get lucky in making some device , I'll denote money to your hair restoration. :)

 

[sophiecentaur]

The fact is that Capacitors and the rest of electrical circuit work is complicated. The only language that describes most electrical phenomena well enough is Maths. In fact, the whole of Science uses Maths and has done since the time when Newton, Leibnitz and others started to get it systematised. Refusing to use Maths will pretty soon end up with that bridge collapsing or a fuse blowing. That's not to say you can't do construction projects and have success. But understanding what happened would be another thing altogether. 'Common English' doesn't put up satellites or make your computer work.


Your English is really fine, btw. I could not hope to discuss things to such a level in any other language as you are doing in English. I can socialise OK in French but it would be hard to get across any Science concepts.

I'm looking forward to receiving that cheque in the post. I will go straight down to the hairdresser's and sort out a wig for myself when it comes.