Can the Dielectric Permittivity of a Material Be Altered?

[Mr.Bomzh]

Ok Sophie , here are my answers.

First of all I never said that changing the dielectric would be basically different than moving plates , I understand it;'s the same thing just one is longer lasting solid state the other is mechanical and probably less efficient that's all.
Also excuse me for not telling this but I never considered this apparatus would not need energy input , ofcourse it would need energy input as the charge flowing back and forth through the transformer would be lost r better said transformed to the secondary which would be under load , say a resistor.
So +ve attached and a load on the secondary was in my head all the time I just have been focusing more on the primary driving idea as the other factors like energy supply and load is nothing new.
So on each cycle one cap would charge up the other would discharge and the lost charge due to emf and induction on the loaded transformer would be replaced by the incoming charge from the +ve supply just as in other cirucits.

Now , if only the dielectric could be made to change like in a mosfet the gate opens and closes the transistor based on applied charge and electric field inside the device , it could actually be a pretty efficient and cool device would it ?
So the pirnciple works, +ve supplied, transformer if its properly made, is a efficient device as we know it, a capacitor also has no problems in terms of efficiency , so the only quesion is for the dielectric and how to vary it , I;m not saying that such a material is possible to make , also I;m not saying how good it wuld be as I don't have nor the calcualtions nor a physical prototype to back it up , I am just asking you to do a little imagine thing.
So if for example a dielecric could be made , not saying it's possible just if, that varies when a charge is applied to it then , I could use a circuit which just drives some charge to one caps dielectric and then back into the other , pretty much like a gate controller IC applies and drains the charge from mosfet gate to either open it up or close it.The charge is not lost in that case , the energy either , it;s just transferred from one place to the other.

Ofcourse as I said I don't know how would the material need to be made to inherit such properties like varyable permittivity upon applied charge and it would probably need to be some mixed material as you cannot apply a charge to a pure delectric.
Well I hope you understand that this is more about the idea than a physical device, and yes some physical moving plates or other device like that would be very innefficient ofcourse , also would probably occupy too much space for a given power output , so the only thing that comes to mind is a special type of dielectric, it it's possible ofcourse.

 

[sophiecentaur]

I can see that your circuit could be made to operate as an inverter circuit if you swapped these non-existent Capacitors for Mosfet switches. One big difference, however, would be that the power would come from the battery that's in the diagram (you would have DC paths when the mosfets are on). In your proposal, you need another source of power.
Your capacitor would need to be made from a form of Unobtanium that is often proposed in Forums. I could also suggest a special form of core for the transformer that could alter the permeability of the core and, thus, produce a varying voltage.

I have a feeling that your OP would have been better if you had asked for opinions on methods for carrying dielectrics than trying to introduce a really whacky, alternative way of producing AC. I could imagine that a useful transducer could be worthwhile producing if you could find some pressure / temperature / pH sensitive material that could be fashioned into a variable capacity probe.

 

[Mr.Bomzh]

well I thought about these caps because ofcourse transistors are really good and they do fit in many many applications , it's just that in power supplies I have never liked them for one reason , using high frequencies they need very very accurately made transformers and other drive electronics otherwise they go smoke and flashes as every time they are turned on they form a physical current path from + to - and we all know that.
a capacitor on the other hand charges up and down but as long as you don't abuse them with overvoltage , overheating or other easy to watch out things you could change the frequency put overload on the secondary and many other things and nothing bad would happen , because all that can happen is the cap gets charged less or faster or slower but that doesn't matter as it won't destroy the device, I kinda have sympathy towards rugged and simple inventions, devices etc.

what do you mean by another source of power ? apart from the rectified +ve and ground or battery +ve and negative what other source of power are we talking about ?

yes I agree i could have made my OP better , but then again what would that change? As in the end I still desire to make a " wacky" hopefully great way of making AC from that DC.
I will look up that material you posted.
well even if this idea is totally crap and nonsense , I'm not shot down myself , the bets have been against me for most of my life anyways , not that something would have changed suddenly.Anyway thinking these ideas even if they are not possible is a good way of learning and understanding the basic stuff that we already have in a better way.
So thank you for patience , also I wish good luck with your hair, so that it would remain in a solid state :D
Hope to hear from you further and in other threads that I will make probably. :)

 

[Mr.Bomzh]

Damn I just took a better look at the word Unobtainium and realized that it is a fictional thing for something one cannot obtain :D:D
Almoust feels like April Fools' Day. :D
Thank god I didn't call some local chemistry or hardware shops asking for it.

 

[sophiecentaur]

what do you mean by another source of power ? apart from the rectified +ve and ground or battery +ve and negative what other source of power are we talking about ?

)

You can answer this question yourself if you can explain how that battery, on your diagram can actually deliver any energy (yes, energy) into your system. It's a DC battery, AC coupled into a circuit. THINK!

 

[Mr.Bomzh]

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?

 

[sophiecentaur]

@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.

 

[Mr.Bomzh]

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 ?

 

[sophiecentaur]

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.

 

[Mr.Bomzh]

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 ?

 

[sophiecentaur]

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.

 

[Mr.Bomzh]

Ok , instead of guessing myself , maybe you can tell then what is that source if not the battery ?

 

[sophiecentaur]

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.

 

[Mr.Bomzh]

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

 

[sophiecentaur]

Geronimo!

 

[Mr.Bomzh]

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

 

[sophiecentaur]

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!

 

[Mr.Bomzh]

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 ?

 

[sophiecentaur]

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.

 

[Mr.Bomzh]

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.

 

[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.