Can the Dielectric Permittivity of a Material Be Altered?

In summary, the conversation discusses the possibility of creating a dielectric material with variable permittivity for use in a capacitor. The concept of a "charge pump" capacitor is also mentioned, where the capacitance can be changed to control the flow of charges in a circuit. However, it is noted that this would require additional switches and may not be practical. The idea of using a varactor diode as a variable capacitance solution is also brought up, but it is mentioned that this would involve putting energy into the system. The conversation concludes with a discussion about the behavior of a capacitor with variable dielectric in a circuit and whether the charges would flow away or stay on the plates.
  • #36
the only reason a battery could not work is because a capacitor has no physical charge flow through it , so the positive charges even though being attracted by the negative ones would want to flow towards them they would stop doing so with time because in a battery the charges need to physically interact, is that the reasoning ?

ok then what would happen in the case of a rectified mains power supply , would it also be a no go?
 
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  • #37
@Mr.Bomzh
You have not read a word that I have written about the energy situation. You have been so sure that your idea is OK that you haven't stopped to think it has a fatal flaw. That battery can give you NO ENERGY, the way you are using it. Do you not realize that?
Energy delivered = Net charge times PD. There is no net charge so no energy.
 
  • #38
wait so you mean that because the capacitors altogether have a total amount of charge which is just passed back and forth but cannot get bigger or change because it has nowhere to go other than just from one plate to another so no new charge can come in and no energy with it , is that what you are trying to say ?
 
  • #39
Mr.Bomzh said:
wait so you mean that because the capacitors altogether have a total amount of charge which is just passed back and forth but cannot get bigger or change because it has nowhere to go other than just from one plate to another so no new charge can come in and no energy with it , is that what you are trying to say ?

That's what I have been saying and implying all along. You have just chosen not to read it.

The energy that can be transferred must come from the process of changing the Capacitance - which is what I have been telling from the start.
 
  • #40
I guess I was high on physics and your statements kinda slipped my eyes:D

Still it kinda puzzles me , okay the total amount of charge doesn't change it just travels frokm one side to the other , but isn't this more about fields , because as the charge goes from one side where the charged cap is to the other where the empty cap is it goes through the transformer primary and with a load on the secondary it endures a back emf which should , I don't knwo how to say this properly, diminish the strength of the charge , as energy was put into the secondary so it had to go away from the primary side, now as this has happened without the +ve supply there would be much less voltage to charge up the other cap as some of it would have dropped while passing through the primary , so the +ve is there to deliver this missing piece so that the cap could get charged to the same value the one before it did?
Ok I guess there will be a problem in my reasoning like 99%, could you please explain this ?
 
  • #41
It's about Potential, rather than fields. E = QV
The charge changes as the Capacitance changes. ("Strength of Charge" is not a meaningful quantity.)
At the risk of repeating myself, work has to be done ON and / or BY the capacitor in order to change the Capacity because charge will flows in and out of it. There has to be a source of energy to make up for any difference in the Energy In and the Energy Out, over the cycle. That source is not the battery - as you have it connected. Thise two capacitors just take and deliver charge in and out of the battery. The net flow of charge is zero and the net flow of energy is zero (from those battery terminals). But there is a flow of energy from the (separate) source that is causing the C to change and the resistive load on the secondary.

You are still trying to make up and apply your own rules about this and they are wrong /inadequate. Just use the accepted rules of circuit analysis (learn them for the first time if you need to) and the logic of what will and won't work will become clear.
 
  • #42
Ok , instead of guessing myself , maybe you can tell then what is that source if not the battery ?
 
  • #43
Hair is starting to look very dodgy now. I'm almost knee deep in the stuff.
YOU have to provide the energy from somewhere or nothing will happen. That's what the motor idea, and others, was all about. Try reading back through the 40 or so posts. It's all been said several times back there. You just ignored it every time.

You kept denying you were talking PMM but that's exactly what you have been doing - without realising it.
 
  • #44
Oh ok , then the energy that would be put into the dielectric change would be the one which would be transferred through the charge flow between the plates through induction through the core to the secondary into the resistor? I hope I finnaly got it , if not then I will take a time off to catch some breath and think about it
 
  • #45
Geronimo!
:biggrin:
 
  • #46
Oh my god , feels like a relief , similar to that which you have after a visit to the dentist. :D
so the field is involved after all as the energy put into the dielectric change does not physically touch the charges that flow between the positive plates of the primary yet it affects them , still geronimo ? :D
 
  • #47
What do you actually 'Know" about the Field? What do you actually Care about the Field? Depending on how you actually change the Capacity, the field (volts per metre) may or may not change.

That bit about "physically touching" is gobbledegook, aamof. :bigeye:

In electrical matters it's pretty much always Potential that counts. CRTs and insides of valves are where you need to think about Fields - everywhere else we talk Energy aka Potential.
Just make an effort to discuss this stuff in the same terms that you find in textbooks and we will all be talking the same language. Home brewed Science speak is a potential pitfall. Behave or I'll get my drill out!
 
  • #48
or you will have to put the drill back and visit the barber , as I think a storm has been passing around lately influenced by this thread :D anyways big thanks for keeping up with my crazy ideas , oh just one more thing , so if we now finally both understand how this could work then where comes in the huge inefficiency you were talking about ? as in all places to my understanding energy is conserved and one action pushes or does the other one and so until the energy gets to the last point which is the resistors in whcih it dissiaptes itself as heat , not to mention the resistance of tghe wires and coils and some leakage from flux etc , in other words all the typical stuff a power supply encounters where does the extra stuff come in into this proposed circuit ?
 
  • #49
Your proposed circuit, as you have drawn it, has no loss mechanism because you don't include the load. Ignore the non-ideal component resistances.
The huge inefficiency is in getting the Capacitance to vary without any internal losses. We're talking Hysteresis here. You unobtanium would need to be stressed in some way to change its dielectric constant - rubber?? Plastic with bits embedded in it? Radiated with X-rays? The sky is the limit but any of those methods involve wasting energy just to produce a change in C. There are Varactor diodes which are reverse biased diodes in which the depletion layer varies as the bias voltage changes. Relatively little loss in a reverse biased diode but, on the other hand, only a a variation of a few tens of pF. That would necessitate a pretty high operating frequency and there are losses associated with that.
I think I'll stick to conventional ideas for inverters until your onobtanium becomes obtanium. Switching components for inverters are required to have very very low on-resistances to avoid losses and overheating. The same (or equivalent) would be needed for your system.
But it is true (and you can console yourself with this) that the effect you are considering could be the basis of a measuring device- with a small signal coming from a transducer which could measure, say, pressure. HAHA I just realized that an electret microphone works in more or less the same way - varying capacitance of a vibrating foil as sound hits it- but still no fancy dielectric trick.
Keep up being inventive but don't forget to learn all the basics if you want to make your in-head inventions work in-practice.
 
  • #50
Well a few tens of pF chnage for my application is really too small as like you said it would require almoust Ghz range frequencies , in other words i think one can achieve much greater capacitance change and lower the frequency respectively.

Oh by the way , while doing google I stumbled across something like this .

http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1645641&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D1645641

Does somebody has obtained unobtainium here ? :D
I must said I read only the preface as I don't have the account there to download that thing in full text.maybe someone has and can do me a great favour , even though I'm not sure if there is valuable information after the fancy cover.
 
  • #51
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.
 
  • #52
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.
 
  • #53
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?
 
  • #54
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.
 
  • #55
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.
 
  • #56
"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.
 
  • #57
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?
 
  • #58
I really can't tell.
 
  • #59
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.
 
  • #60
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.
 
  • #61
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
 
  • #62
It's like water on stone - you get to me eventually.
:bugeye:
wibble wibble wibble

Are you familiar with the 'beans' sequence in Blackadder?
 
  • #63
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
 
  • #64
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.
 
  • #65
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. :)
 
  • #66
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. :smile:
 
<h2>1. Can the dielectric permittivity of a material be increased?</h2><p>Yes, the dielectric permittivity of a material can be increased through various methods such as doping, applying an external electric field, or changing the temperature or pressure of the material.</p><h2>2. What factors affect the dielectric permittivity of a material?</h2><p>The dielectric permittivity of a material is affected by factors such as the type of material, its chemical composition, temperature, frequency of the applied electric field, and the presence of impurities or defects.</p><h2>3. Is it possible to decrease the dielectric permittivity of a material?</h2><p>Yes, the dielectric permittivity of a material can be decreased by introducing impurities or defects, applying an external magnetic field, or using a different type of material with a lower dielectric constant.</p><h2>4. How does the dielectric permittivity of a material affect its electrical properties?</h2><p>The dielectric permittivity of a material is directly related to its ability to store electrical energy and its ability to withstand an applied electric field. A higher dielectric permittivity means a higher capacitance and a stronger response to an external electric field.</p><h2>5. Can the dielectric permittivity of a material be altered permanently?</h2><p>Yes, the dielectric permittivity of a material can be permanently altered through processes such as polarization, which involves the alignment of dipoles within the material, or through irreversible chemical reactions that change its chemical composition.</p>

1. Can the dielectric permittivity of a material be increased?

Yes, the dielectric permittivity of a material can be increased through various methods such as doping, applying an external electric field, or changing the temperature or pressure of the material.

2. What factors affect the dielectric permittivity of a material?

The dielectric permittivity of a material is affected by factors such as the type of material, its chemical composition, temperature, frequency of the applied electric field, and the presence of impurities or defects.

3. Is it possible to decrease the dielectric permittivity of a material?

Yes, the dielectric permittivity of a material can be decreased by introducing impurities or defects, applying an external magnetic field, or using a different type of material with a lower dielectric constant.

4. How does the dielectric permittivity of a material affect its electrical properties?

The dielectric permittivity of a material is directly related to its ability to store electrical energy and its ability to withstand an applied electric field. A higher dielectric permittivity means a higher capacitance and a stronger response to an external electric field.

5. Can the dielectric permittivity of a material be altered permanently?

Yes, the dielectric permittivity of a material can be permanently altered through processes such as polarization, which involves the alignment of dipoles within the material, or through irreversible chemical reactions that change its chemical composition.

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