| Steve Eddy |
| quote: | Originally posted by fdegrove
Dielectric hysteresis decreases as the loss angle of the dielectric increases. |
Dielectric hysteresis is reduced as the loss angle decreases and becomes zero when the loss angle is zero.
| quote: | | Hopefully that's sufficiently clear too see that DA and DH are not one and the same . |
Since dielectric hysteresis is reduced as the loss angle decreases, how does that make it sufficiently clear to see that DA and DH are not one and the same?
se |
|
|
| john curl |
Any hot shots out there? Can any of you do a circuit simulation?
If so, then try this: Make a differential subtractor with an ideal instrumentain op amp simulation. Cap couple both inputs, and drive them from the same signal. Have equal value R's to ground on each input. As some of you probably realize, if the caps are the same value and create the same RC time constant on both the = and - input, then they will cancel out.
Now create a model of a moderate DA capacitor by adding series RC's in parallel to one of the input caps. You can find this data by looking around on Pease's soakage article. Then try different test signals at the input, after you have slightly adjusted one side for the best null with the test signal that you are using. Try a sine wave, try a sine wave sweep, try a square wave.
Then try an asymmetrical pulse. Note the difference. Report it here. Test results should be in by the end of the week. Hint: you should find a big difference between symmetrical input signals and asymmetrical input signals. |
|
|
| Steve Eddy |
| quote: | Originally posted by john curl
Hint: you should find a big difference between symmetrical input signals and asymmetrical input signals. |
Who said that you wouldn't?
se |
|
|
| john curl |
| How about a 10,000:1 difference? |
|
|
| Christer |
(Shortcut: possibly relevant references at the end of post)
In a forum discussion with a lot of people participating, there
is always confusion about who says what and who thinks what
and we tend to lump people together into two or, at most,
three different camps to make things manageable. This is
of course always unfair, since often there are as many opinions
and standpoints as there are individuals.
Just to clear it out, I have not made any claim about whether
there is or is not such a phenomenon as dielectric hysteresis
and which is distinct from dielectric absorption. I have just
commented that it there Í have found no support for such
a phenomenon in those references and claims made about
it so far. I know of course, I could have made more extensive
web searches than just searching for the exact phrase, and
some grammatical variations of it, that Franks suggested, but
am I to find proof of his claims??? The main reason I posted
my fails results was that I found them quite funny in this
context.
Since I anyway can't do much useful in the mornings until I
have had more coffee than is good for me I decided to do
some more web search on the topic. I didn't wade through all
of what came up but let me give you the three possibly relevant
pointers pointers I found:
1) The quote "the dielectric hysteresis decreases as the loss angle of the dielectric increases" which Frank failed to give a
reference to can be found in this patent application
http://www.nia.org/timeline/text/1708038.htm
I didn't read much of it, since I hate reading patent applications
and they are anyway often just unsubstantiated claims.
2) I found a database entry for a IEEE symposium paper, but
no link to the paper, with the title "Apparent dielectric hysteresis without significant dipolar movement?" which might be of
interest, since DA requires dipolar movement. I don't have the
time or patience to try digging up the paper right now, at least.
http://fodok.jku.at/fodok/publikation.xsql?PUB_ID=9271
3) A thesis abstract having "dielectric hysteresis" among the
keywords. There is no indication in the abstract, however,
what the term means or if it is different from DA. Just like paper
2, however, it is from Austria, so maybe they are related.
http://www.arcs.ac.at/dissdb/rn038176
Now I've done my share of the work for the moment, or more
than that, so now I suggest somebody else go dig up these
papers if they care. I would personally start with #2, which
seems most likely to shed some light on the issue.
Edit: Considering recents posts by Frank and John, I should add
that my assumption has all the time been that DH is supposed
to appear not only in ceramic and electrolytic caps, which we
already know behave in peculiar ways of their own. |
|
|
| fdegrove |
Hi,
Well done, Christer.
I suppose it's worthwhile to actually do more than just a quick glance at the first page of the Google results.
Which is what I did and it's rather time consuming as you may now realise yourself.
Even more so when you actually read the interesting references.
So, may I suggest a few more coffees and some reading of the references you've just quoted?
Cheers,;) |
|
|
| Christer |
Frank,
You don't have to tell me it is time consuming to seach the web,
I have known that for years. :)
The thing is, you made the claim, so you have supposedly found
papers supporting your claims, so why not point us to them?
The burden of proof is usually with the one who makes the
claim.
Is any of the three references I found worth reading, for instance?
Don't have time for more coffee or reading for the moment
(no I don't mean dipole moment as in DA :) ). |
|
|
| fdegrove |
Hi,
| quote: | | The thing is, you made the claim, so you have supposedly found papers supporting your claims, so why not point us to them? |
Would I dare to make the claim if I didn't know what I was talking about?:angel:
Pointing to references is no guarantee that people will actually read them, making them look them up themselves will at least teach them where and how to find them.
Sounds arrogant, I know, but sometimes it's the best way to go.
| quote: | | Is any of the three references I found worth reading, for instance? |
The Wilson patent is really old but worth reading.
The Austrian ones I vaguely remember as being both more or less the same but I'll need to reload them and see what's in them.
This one I found worth going through as it's more related to audio issues:
WEBER
Cheers,;) |
|
|
| fdegrove |
Hi,
| quote: | | The Austrian ones I vaguely remember as being both more or less the same but I'll need to reload them and see what's in them. |
Reference 2) is not worthwhile, 3) is a summary of a dissertation and is of interest to me as it treats another one of my pet topics related to audio wire namely dielectric barrier microdischarges.
Which is probably the origin of the "micro diode" theory blurb.
Cheers,;) |
|
|
| SY |
The dipolar motion made me wonder about temperature dependence of DA- how much does it reduce going from (say) 60 degrees C down to 20 degrees C? Can one improve cap performance by intensive cooling? I would think that the T-dependence would follow a Boltzman law below the Tg of the dielectric, so this could be a significant effect ("significant" in the context of the miniscule effects we're discussing).
John, did you do any kind of gauge repeatability and reproduceability study on your test setup for the wire measurements? Can you share the results? |
|
|
| fdegrove |
Hi,
| quote: | | The dipolar motion made me wonder about temperature dependence of DA- how much does it reduce going from (say) 60 degrees C down to 20 degrees C? Can one improve cap performance by intensive cooling? I would think that the T-dependence would follow a Boltzman law below the Tg of the dielectric, so this could be a significant effect ("significant" in the context of the miniscule effects we're discussing). |
Possibly so but wouldn't that also change the capacitors' value?
I'm thinking about the TKc factor here.
Cheers,;) |
|
|
| SY |
| Yes, though at a much slower rate than the change in DA, since the dielectric constant doesn't involve molecular or domaine motion, just polarizability. |
|
|
| IanHarvey |
| quote: | Originally posted by john curl
Any hot shots out there? Can any of you do a circuit simulation?
...
Now create a model of a moderate DA capacitor by adding series RC's in parallel to one of the input caps.
Try a sine wave, try a sine wave sweep, try a square wave.
Then try an asymmetrical pulse. Note the difference. |
Can I propose an alternative experiment, as follows?
1. Feed an input signal (of whatever kind), and note the output signal.
2. Analyse the frequency spectrum of the input signal - note which harmonics are present.
3. Similarly, analyse the frequency spectrum of the output signal.
4. Note and report whether any frequencies are present in the output signal which are not in the input signal.
The point of this experiment is that you don't need a simulator. Maths will simply show that the only frequencies present in the output were present in the input to start with, no matter how many parasitic capacitors, resistors and inductors you add.
Why am I bothered? Well, if DA is completely and accurately modelled by parasitic R's and C's, it cannot be the cause of any frequencies present in the output which weren't in the input (which is what I understand by terms such as nonlinearity and distortion). Its effects can be completely defined with a few simple, easily measurable parameters (e.g. frequency response). In other words, weird measurement techniques won't tell you anything that straightforward ones don't.
If DA can't be modelled like this (and, for instance, magnetic hysteresis effects in iron-cored inductors can't be modelled with parasitic R's and L's) then it's more interesting. If anyone has measurement results which can't be made to fit an R/C network model, let us all know - this is definitely new territory.
Cheers
IH |
|
|
| Steve Eddy |
| quote: | Originally posted by john curl
How about a 10,000:1 difference? |
A 10,000:1 difference in what?
se |
|
|
| Steve Eddy |
| quote: | Originally posted by Christer
(1) The quote "the dielectric hysteresis decreases as the loss angle of the dielectric increases" which Frank failed to give a
reference to can be found in this patent application
http://www.nia.org/timeline/text/1708038.htm
I didn't read much of it, since I hate reading patent applications
and they are anyway often just unsubstantiated claims. |
Yes, and what I responded with, which was the exact opposite of what Frank had stated:
Dielectric hysteresis is reduced as the loss angle decreases and becomes zero when the loss angle is zero.
Is from the same document.
By the way, you should read it. Even though it's nearly 80 years old, much of what's said in it wouldn't be out of place in some "white paper" written today by a high-end cable manufacturer.
se |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Pointing to references is no guarantee that people will actually read them, making them look them up themselves will at least teach them where and how to find them. |
Did you even read the one you copied this statement from:
The dielectric hysteresis decreases as the loss angle of the dielectric increases.
If you had, you'd have found that it also contains this statement:
Dielectric hysteresis is reduced as the loss angle decreases and becomes zero when the loss angle is zero.
How do you explain these two diametrically opposed statements?
se |
|
|
| janneman |
You know, after all this sqirmishing around, one can only conclude that neither John C, Frank or Chirster have any clue what they are talking about on these subjects.
I think this thread has degenerated to the the level of being disgusting.
It would be a major step forward if you all would start to act like grown-ups. But then again, I've been disappointed before.
Continue your mental, content-less masturbation, but without me. Which isn't a loss anyway.
Jan Didden |
|
|
| fscarpa58 |
Hi all,
I do not know DA but I study hysteresis phenomena from magnetic ones to those associated to
the adsorption of water by a porous media. I think, IMHO, that if this hysteresis is a linear one
the name hysteresis is incorrect.
Hysteresis is a nonlinear phenomenon, in some sense it is two times non-linear.
when I have a linear system ( e.g. a circuit containing only resistance, caps., inductors
and linear active devices ) I can describe it with a system of linear differential equations
with constant coefficients. When some devices are non linear the equation in the system become nonlinear, that is I can read terms, in the equations, that are a nonlinear function of the state variables (e.g. voltages and currents ). From here the terms “nonlinear system”, “non linear distortion”, etcetera.
When these nonlinear terms show discontinuities or are governed by “if … then” rules then
hysteresis may arise, or not. It may depend or not on freq. but certainly the behavior of a hysteretic system depends on its history.
Federico |
|
|
| john curl |
| Wake up folks, DA is usually defined and modeled as a LINEAR DISTORTION compared to nonlinear distortion, which is measured by harmonic or IM distortion measuring instruments. DA can still be many percent of the audio signal per cap. Sine wave analysis will hide DA, so a cap with, let's say 5% DA, will have less than .0005% harmonic distortion. What is that ratio? Quiz on Friday. |
|
|
| Steve Eddy |
| quote: | Originally posted by IanHarvey
The point of this experiment is that you don't need a simulator. Maths will simply show that the only frequencies present in the output were present in the input to start with, no matter how many parasitic capacitors, resistors and inductors you add. |
Quite so. Even if your waveform is asymmetrical.
| quote: | | Why am I bothered? Well, if DA is completely and accurately modelled by parasitic R's and C's, it cannot be the cause of any frequencies present in the output which weren't in the input (which is what I understand by terms such as nonlinearity and distortion). |
Correct.
Though alterations in frequency and phase response is considered "linear" distortion.
se |
|
|
| Steve Eddy |
| quote: | Originally posted by john curl
Wake up folks, DA is usually defined and modeled as a LINEAR DISTORTION compared to nonlinear distortion, which is measured by harmonic or IM distortion measuring instruments. DA can still be many percent of the audio signal per cap. Sine wave analysis will hide DA, so a cap with, let's say 5% DA, will have less than .0005% harmonic distortion. |
Since DA is modeled as a linear distortion, a cap with 5% DA will have 0% harmonic distortion.
se |
|
|
| fdegrove |
Hi,
| quote: | | The dielectric hysteresis decreases as the loss angle of the dielectric increases. |
Yes, Steve, I did notice the mistake in the text.
If you read the next line of text it becomes clear that the author meant the opposite.
By referring to the Affel and Green patent application from which you quote the apperently diametrically opposing statement that becomes even clearer and confirms the intention of the author.
Note also that the patent was filed in 1925.
Moreover by actually understanding the phenomen as you showed, you also seem to confirm that you understand that in fact hysteris distortion is not the same as dielectric absorbtion.
Why we keep dragging this on and on is beyond me though...
I think I have already hinted at where the "microdiode" idea came from twice.
Hint 3 : It's just an analogy written up by some poor soul trying to explain to the masses why he felt convinced cables could distort the audio signal.
Probably promoting one or other supercable sold at ten times the industrial catalogue price.
Hope this helps,;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Yes, Steve, I did notice the mistake in the text.
If you read the next line of text it becomes clear that the author meant the opposite.
By referring to the Affel and Green patent application from which you quote the apperently diametrically opposing statement that becomes even clearer and confirms the intention of the author. |
If you noticed the mistake in the text, then why did you quote the MISTAKEN TEXT and use that as proof that DA and DH weren't one and the same?
| quote: | | Note also that the patent was filed in 1925. |
Yes, I noticed that. So? It didn't stop you from quoting from it.
| quote: | | Moreover by actually understanding the phenomen as you showed, you also seem to confirm that you understand that in fact hysteris distortion is not the same as dielectric absorbtion. |
"Hysteresis distortion"? No, the term we'd been using has been dielectric hysteresis. And again, I see no evidence that dielectric hysteresis and dielectric absorption are not synonyms for the same phenomenon.
| quote: | | Why we keep dragging this on and on is beyond me though... |
Because you haven't shown that dielectric hysteresis and dielectric absorption are not synonyms for the same phenomenon.
se |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Yes, though at a much slower rate than the change in DA, since the dielectric constant doesn't involve molecular or domaine motion, just polarizability. |
Wait a minute, how can a material polarize without the movement of the polarizable elements which allow it to be polarized in the first place? SOMETHING'S gotta move unless you're talking about a vacuum.
se |
|
|
| fdegrove |
Hi,
| quote: | | If you noticed the mistake in the text, then why did you quote the MISTAKEN TEXT and use that as proof that DA and DH weren't one and the same? |
It's just that I hadn't noticed I had selected the wrong block of text while posting, that's all.
| quote: | | Yes, I noticed that. So? It didn't stop you from quoting from it. |
Just hoping we'd stop discussing it before 2025, that's all.:D
Cheers,;) |
|
|
| Christer |
| quote: | Originally posted by janneman
You know, after all this sqirmishing around, one can only conclude that neither John C, Frank or Chirster have any clue what they are talking about on these subjects.
I think this thread has degenerated to the the level of being disgusting.
It would be a major step forward if you all would start to act like grown-ups. But then again, I've been disappointed before.
Continue your mental, content-less masturbation, but without me. Which isn't a loss anyway.
Jan Didden |
Interesting, I am not sure I made much of a claim about
anything so there even can be anything I am not having
a clue about. I thought I had mostly tried to demand some
clarification of other peoples claims and tried to structure up
some things. Obvoiously I have said something else that
was very wrong or stupid and that has slipped passed both
myself and others. I usually want to know about my mistakes
so I can admit them, so could you please reconsider your
opinion not to post anything more and tell me what I did
wrong? Or do you just want to join in and complain about
others without contributing anything useful yourself? Show
us you are adult by not just complaining, but also telling us
what you are complaining about.
Edit: I do, however, agree with you that the thread has
degenerated and is losing its focus on the original issue. |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
It's just that I hadn't noticed I had selected the wrong block of text while posting, that's all. |
Ok, so if the right block of text is the block of text which says that as dielectric hysteresis increases the loss angle also increases, how does that make it "sufficiently clear too see that DA and DH are not one and the same" seeing as the loss angle increases as DA increases?
| quote: | | Just hoping we'd stop discussing it before 2025, that's all.:D |
Or at least before it becames all too clear that you're just grasping at straws here. :D
se |
|
|
| SY |
| quote: | Originally posted by Steve Eddy
Wait a minute, how can a material polarize without the movement of the polarizable elements which allow it to be polarized in the first place? SOMETHING'S gotta move unless you're talking about a vacuum.
se |
Charge density moves. It's not massless, but pretty damn close compared to the weight of the nuclei plus core electrons. |
|
|
| Christer |
To late to add to previous post by editing.
Jan,
I have just reread, alhthough quickly, all what I wrote in this
thread, and all that you wrote to, BTW, and I am even more
puzzled what you might be referring to. Since you lumped
me, John and Frank together but left, for instance, Steve out,
you seem to think I have made some claim in agreement
with Frank and John and which is wrong, while at the same
time it seems you agree with Steve. I cannot see I have made
any such claims. However, you have made claims that I intepret
as agreeing with Frank and John while not agreeing with Steve.
This is really puzzling. Maybe I am confusing you by not taking
a clear stand and claim anything at all? you see, I don't want
to make claims about whether a certain pehnomenon exists
or not without having evidence of it, as some people inlcuding
you seem not to mind.
Jan, I beg you for a clarification of what you "accused" me of,
either here or by email. I don't wan't to be accused of
making errors without getting a chance to either admit it
or clarify myself. |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Charge density moves. It's not massless, but pretty damn close compared to the weight of the nuclei plus core electrons. |
What about molecular dipoles?
se |
|
|
| SY |
| Polarity and polarizability are two different things. |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Polarity and polarizability are two different things. |
I'm talking about polarizability. And one of the things which determines the polarizability of a dielectric material is the re-orientation of molecular dipoles.
se |
|
|
| fdegrove |
Hi,
| quote: | | Or at least before it becames all too clear that you're just grasping at straws here. |
Let's just hope they're good straws then.
Seriously, Steve, there are literally hundreds of academic references for all to see and read on the web, do you really expect anyone to go through all of them untill there's one that might just suit you?
| quote: | | Polarity and polarizability are two different things. |
Careful, you may have to prove that too...;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Let's just hope they're good straws then. |
Even the best straw is still just a straw.
| quote: | | Seriously, Steve, there are literally hundreds of academic references for all to see and read on the web, do you really expect anyone to go through all of them untill there's one that might just suit you? |
So let's see just one which actually differentiates dielectric absorption from dielectric hysteresis. You don't have to go through all of them. You just have to go through one. And 1925 patents don't count as "academic references" by the way.
se |
|
|
| fdegrove |
Hi,
| quote: | | And 1925 patents don't count as "academic references" by the way. |
Ah, I was afraid of that already...Mr. Wilson or any other patent holders, tear them up they're worthless rags.
What would count, I wonder?
Put it another way, what would count as good enough to convince you?
Maybe there's a way to tell the search engines to find something SE likes and accepts as being either black or white enough to be accepted....
Just kidding, Steve, but sometimes you make me tear out the few straws on my head that are still hanging in there.
| quote: | | You just have to go through one |
Which would be?
Cheers,;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Ah, I was afraid of that already...Mr. Wilson or any other patent holders, tear them up they're worthless rags.
What would count, I wonder?
Put it another way, what would count as good enough to convince you? |
The patent's fine. You said yourself it was clear what the author meant to say. Which was that as dielectric hysteresis increased, the loss angle increases as well.
But that's perfectly in keeping with dielectric absorption. So it only argues against your claim.
| quote: | Maybe there's a way to tell the search engines to find something SE likes and accepts as being either black or white enough to be accepted....
Just kidding, Steve, but sometimes you make me tear out the few straws on my head that are still hanging in there. |
It's real simple, Frank. Either offer up something which explains what the difference is between dielectric hysteresis and dielectric absorption, or simply explain it in your own words.
Which would be any one of the hundreds that you say are out there.
se |
|
|
| Steve Eddy |
Here's the conundrum, Frank.
You keep insisting that dielectric hysteresis and dielectric absorption are two different things. Yet it's clear that you don't have the foggiest idea just what that difference is. Which begs the question, if you don't know what the difference is, how is it that you know that they are two different things?
se |
|
|
| fdegrove |
Hi,
ROTF.
| quote: | | But that's perfectly in keeping with dielectric absorption. So it only argues against your claim. |
Yes, in the patent application one could replace one for the other and it would still be true.
How does that make both synonymous?
| quote: | | Which would be any one of the hundreds that you say are out there. |
You seem to think I'm an employee of yours so what's the amount on the payroll?
But yes, the Google first page shows hits good for 10 pages with 10 references per page that amounts to a hundred references.
Come to page 10 and even more turn up...
Naturally all these references are wrong and confuse DA with DH, they just must be wrong because there's just not enough of them.
And don't give me any **** like you made the claim so the onus is on you. You have the same resources as I have, perhaps even more when it comes to library access etc.
Does it not seem odd to you that no one but you makes this claim of synonymousity?
And no, I don't think it has any effect on audio cables of decent quality and shape but it's your call.
Cheers, ;)
P.S. Just lost another bunch of those straws hanging from my head....:bawling: |
|
|
| SY |
| quote: | Originally posted by Steve Eddy
I'm talking about polarizability. And one of the things which determines the polarizability of a dielectric material is the re-orientation of molecular dipoles.
se |
Not exactly, and especially not for common materials used as cap dielectrics. Take a simple polymer like polyethylene, for example; the dipoles within the molecules are quite weak (carbon and hydrogen have similar electronegativity, carbon-carbon single bonds are totally nonpolar). But under a field, the electron density (and hence dipole moment) squishes back and forth. This is a function of the charge cloud sloshing back and forth with the applied field, but to a good approximation (Born-Oppenheimer) the molecular centers aren't moving with the field.
Now, when you measure the dielectric contant of non-macromolecular liquids, for example, the motion of molecular dipoles can become significant. But that's not exactly a typical cap or cable insulation material family. |
|
|
| fdegrove |
Hi,
| quote: | | carbon-carbon single bonds are totally nonpolar |
Am I correct in thinking this is not a polymer but a monomer, so to speak?
If it is a monomer it would also be mono-polar, hence no dipolar movement can take place?
| quote: | | This is a function of the charge cloud sloshing back and forth with the applied field, but to a good approximation (Born-Oppenheimer) the molecular centers aren't moving with the field. |
Fascinating...This is oh so similar to how electron tubes work.
Cheers,;) |
|
|
| SY |
No, polyethylene is definitely a polymer- there's precious little monomer content.
Unlike space-charge, the electrons are still pretty well bound. The induced dipole (as an order of magnitude) is the equivalent of shifting or distorting the electron cloud about a tenth of the diameter of a hydrogen atom. And the nuclei cause the cloud to snap back to the equilibrium distribution pretty quickly once the field is removed.
Geometrically, a polyolefin like polypropylene or polyethylene will resemble a long zig zag structure of carbons all bound in a nearly 1-D chain. The hydrogens (and in the case of polypropylene, the methyl groups) hang off the vertices like little pontoons. |
|
|
| john curl |
You folks can sure make things confusing. ;-)
Now this is how I see it.
First, insulation in caps, wires, etc can and do have DA. Now what do I mean by DA? I mean a tendency for the molecules to be effected by the signal in such a way that they tend to absorb some of what passes through as heat, and some as a delayed release of stored energy or perhaps electrons.
Most caps do not have a DA spec. Why? Because it is not useful to advertise it. For other reasons, they MIGHT have an ESR spec or something else that will imply the heating effects of the cap with varying frequencies. Think about a switching supply. Hi frequency, lots of harmonics, lots of cap current. What will heat up the cap? Well, lead resistance will, as well as dielectric losses of the molecules dancing along with the waveform current, etc. Some dielectrics are better for switching supplies than others.
Now what is the mystery of DA? It is normally a 'linear' distortion. This means that it will NOT generate harmonics or IM byproducts. Darn! How can you measure it then? Well, if you just charge a cap with a DC voltage, then discharge it for many hundreds of time constants (RC's), then the cap should be pretty much discharged then, right? Well, wrong most of the time. The dielectric will capture some of the input voltage and release it in its own sweet time, including several months or years. What does this mean for audio? Well. please think about it. |
|
|
| fdegrove |
Hi,
| quote: | | Unlike space-charge, the electrons are still pretty well bound. |
Got it, no or little heating to release electrons.
| quote: | | And the nuclei cause the cloud to snap back to the equilibrium distribution pretty quickly once the field is removed. |
Think I understand that one too, with AC going through it this is a jo-jo effect, n'est-ce pas?
With DA causing frequency dependent time-lag depending on DC (dielectric constant in this case)?
What happens if we polarize the dielectric by means of a DC (direct current in this case) so that it has a fixed polarity by running a DC voltage on the shielding braid in a coax for instance.
Is that's a possibility or just plain nonsense?
Just aksin' as they say in the West Indies,;) |
|
|
| fdegrove |
Hi,
| quote: | | What does this mean for audio? Well. please think about it. |
Havoc all over the place.
Conclusion: use the best dielectric materials (the ones with low DA and no DH) such as PTFE, extruded if you can afford and find it.
But there's more, so much more...what about paper, cotton as dielectric materials. What about dielectric barrier discharges?
Cheers, |
|
|
| SY |
Frank: Yes, you can induce a dipole moment in a dielectric by DC biasing one conductor wrt the other. The polarization holds as long as the DC will- plus a DA tail. I'm not sure why you'd want to do that.
The time lag that you speak of is fantastically small, which is why polyethylene has low losses up to ridiculously high frequencies. |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Yes, in the patent application one could replace one for the other and it would still be true.
How does that make both synonymous? |
I didn't say it made them synonymous. What it doesn't do is present any sort of distinction. It simply says that dielectric hysteresis is a loss mechanism which causes the loss angle to increase. Dielectric absorption is also a loss mechanism which causes the loss angle to increase.
| quote: | | You seem to think I'm an employee of yours so what's the amount on the payroll? |
No, you are your own employee working in the service of substantiating your own claims, which is your responsibility, not mine.
| quote: | But yes, the Google first page shows hits good for 10 pages with 10 references per page that amounts to a hundred references.
Come to page 10 and even more turn up... |
10 references per page? Damn, Frank, make life easier on yourself and go to Preferences and set it for 100 per page.
| quote: | | Naturally all these references are wrong and confuse DA with DH, they just must be wrong because there's just not enough of them. |
Who says they're confusing DA with DH?
By the way, if I Google for both "dielectric absorption" AND "dielectric hystereis" in hopes of finding something which might actually indicate that there are different explain any differences between the two, I get a grand total of 27 hits, which when the redunancies are removed, comes to a whopping 14.
Other than a couple of high-end cable manufacturer's websites and some Asian, Russian and Polish language glossaries, the closest thing that I found was a piece on signal switches and sample and hold circuits for an electronics class at the University of Denver.
http://www.du.edu/~etuttle/electron/elect25.htm
Which reads:
The choice of hold capacitor is important. The leakage of electrolytics and the transient behavior of ceramics rule them out completely in this application. The best choice is probably polypropylene, which I used, and after that polystyrene or Mylar. Polycarbonate is much inferior to all of these. The greatest problem (after leakage, which should be practically zero) is dielectric hysteresis in which the voltage changes on charge and discharge are not the same. There is also dielectric absorption, where there is a "memory" of past states. A capacitor freshly discharged may acquire a small voltage as time goes by. All of these phenomena are the result of the complexity of dielectric structure and behavior.
A search on "dielectric hysteresis" and "sample and hold" turned up just one hit. Guess which one.
| quote: | | And don't give me any **** like you made the claim so the onus is on you. You have the same resources as I have, perhaps even more when it comes to library access etc. |
And how does that relieve you from the burden of substantiating your claim? Since the responsibility is yours, my doing your work for you would make me your employee. So let me ask you, what's the amount on the payroll?
| quote: | | Does it not seem odd to you that no one but you makes this claim of synonymousity? |
Not one but me? Did you miss the FaradNet glossary reference for dielectric absorption?
Also called dielectric hysteresis or dielectric soak.
se |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Not exactly, and especially not for common materials used as cap dielectrics. Take a simple polymer like polyethylene, for example; the dipoles within the molecules are quite weak (carbon and hydrogen have similar electronegativity, carbon-carbon single bonds are totally nonpolar). But under a field, the electron density (and hence dipole moment) squishes back and forth. This is a function of the charge cloud sloshing back and forth with the applied field, but to a good approximation (Born-Oppenheimer) the molecular centers aren't moving with the field.
Now, when you measure the dielectric contant of non-macromolecular liquids, for example, the motion of molecular dipoles can become significant. But that's not exactly a typical cap or cable insulation material family. |
From Kundert's paper on modeling dielectric absorption:
The permittivity of a dielectric varies with frequency as various mechanisms within the dielectric are excited [2]. As an electric field impinges on a dielectric material, the charge particles in that material will rearrange themselves in such a way as to line their
dipole moments up with the field. This acts to increase the flux density and therefore the permittivity. This is shown for a polar material in Figure 3. Region (1) is in the range of X-rays and above. At these frequencies there is no interaction between the material and the wave, and so the permittivity is the same as the free space permittivity. As frequency decreases the inner electrons (2), the valence electrons (3), and eventually the
atoms (4) themselves successively resonate and make their contributions to the permittivity. Notice that during these resonances the permittivity becomes complex, which indicates that the dielectric becomes lossy. As frequency descends, polar molecules (5), or in some materials, electric domains, become excited and increase the permittivity greatly. For the polar molecules this is called dipole relaxation, while for the electric domains it is called ferroelectric relaxation (so named because of its similarity to ferromagnetism) [1, 15]. These two represent the mechanism behind dielectric absorption. The last process that affects permittivity is called space charge relaxation (6). This is caused by charges that are free to move about but not to recombine at the electrodes. These charges behave at low frequencies like macroscopic dipoles that
reverse their direction each half period. |
|
|
| Steve Eddy |
| quote: | Originally posted by john curl
First, insulation in caps, wires, etc can and do have DA. Now what do I mean by DA? I mean a tendency for the molecules to be effected by the signal in such a way that they tend to absorb some of what passes through as heat, and some as a delayed release of stored energy or perhaps electrons. |
You might want to give Kundert's paper a read:
http://www.designers-guide.com/Modeling/da.pdf
| quote: | | Now what is the mystery of DA? It is normally a 'linear' distortion. This means that it will NOT generate harmonics or IM byproducts. Darn! How can you measure it then? |
In the time domain, John. It will affect frequency and phase resopnse.
| quote: | | What does this mean for audio? Well. please think about it. |
Look at the model, John. Geez, it's just some resistors and capacitors. You mean you can't figure it out?
Here's Pease's model for a 1uF mylar cap:
se |
|
|
| fdegrove |
Hi,
| quote: | | I didn't say it made them synonymous. What it doesn't do is present any sort of distinction. |
Maybe you should take a course on English then?
Come on Sir Lancelot you lost the battle and you know it...
It might take you some DA time lag to realise it though.;)
And for the umpteenth time, DA and DH are NOT synomynous whether you like it or not.
Like I, Bob Pease style, would say, let's not find problems but solve problems: DH is not likely to occur in filmcaps or any half-decent audio cables.
In the mean time I can only suggest you look up both terms in a technical dictionary and maybe, just maybe you'll find that I'm not that wrong after all.
As I mentioned before, there are more important factors at play in audio cables, just keep ignoring those and continue chewing on the same old bone.
| quote: | | And how does that relieve you from the burden of substantiating your claim? |
And my claim is simply that DH is not DA and that's all there's to it.
I'd expect someone integrating xformers into existing OEM product to at least have a notion of the conceptual difference?
It's not up to me to provide you with the proof, there's not a single forum rule saying so....
Guess it's just whishful thinking on your part.
Cheers,;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
And for the umpteenth time, DA and DH are NOT synomynous whether you like it or not. |
Then stop dancing around like Fred Astaire tell us all what the difference is, Frank.
se |
|
|
| fdegrove |
Hi,
| quote: | | Then stop dancing around like Fred Astaire tell us all what the difference is, Frank. |
Much of the difference can be found in the mind of the true thinkers where the abstraction of the model is just that, the model, and the real world is just a mock up of the abstract world.
As you can see Fred Astaire still has some modelling to do taking into account not only mathematical so called scientific models but
also alot of acceptance of the fact that models are what they are;
building blocks for theories.
Some people can never think outside of taught models others toy it with successfully.
Pick your category,;) |
|
|
| kuribo |
Steve-
Stop wasting your time; it is quite clear he is doing nothing but spanking the monkey, and wasting everyone's time with his coy guru-esque doublespeak. |
|
|
| fdegrove |
Frank-
| quote: | | Stop wasting your time; it is quite clear he is doing nothing but spanking the monkey, and wasting everyone's time with his coy guru-esque doublespeak. |
Spot the difference?;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
Much of the difference can be found in the mind of the true thinkers where the abstraction of the model is just that, the model, and the real world is just a mock up of the abstract world. |
Who said anything about the model, Frank?
JUST EXPLAIN WHAT THE DIFFERENCE IS!
| quote: | | As you can see Fred Astaire still has some modelling to do taking into account not only mathematical so called scientific models but also alot of acceptance of the fact that models are what they are; building blocks for theories. |
Again, who said anything about the model?
JUST EXPLAIN WHAT THE DIFFERENCE IS!
| quote: | | Some people can never think outside of taught models others toy it with successfully. |
Yet again, who said anything about the model?
Those who can think can explain. Those who can't just dance.
se |
|
|
| kuribo |
| I think everyone has noticed the difference, that being that you made a claim (DA and DH are different), and Steve asked you to explain the difference. Quite a fair request. You have yet to explain this difference, rather you hide behind mumbo-jumbo, and bait Steve. At that you are a true master. |
|
|
| fdegrove |
Hi,
| quote: | | You have yet to explain this difference, rather you hide behind mumbo-jumbo, and bait Steve. At that you are a true master. |
Time for you to come out of the cupboard and 'splain it to the more brilliant minds.
Mind you, you don't have to and I'm not actually demanding anything from you unlike some somewhat lesser gods. Oopsie.
Again, spot the difference?
| quote: | | You have yet to explain this difference, rather you hide behind mumbo-jumbo, and bait Steve. At that you are a true master. |
Reality check: can anyone bait Steve?
No, Steve is actually looking for bait. Which is where you come in.
As bait???
Good luck but welcome here nonetheless, it does give the wrong impression but we all do get along just fine.
Steve and me we just like to absorb things before we run into hysteresis...
This could just as well turn into....nah...I won't tell.
Cheers,;) |
|
|
| DrG |
Here's my "contribution"...
I know absolutely nothing about DH or DA. But this is the umpteenth thread where the SAME person seems to make loose academic associations and baseless technical claims, leaving the burden of proof on those who dare to dispute his allegations.
Steve is unable to digest this kind of semi-academia at face value, as is the province of a true "scientist", or simply a logical person such as myself. And as before, Steve will simply get dizzy watching the fancy footwork while begging the same futile "JUST EXPLAIN WHAT THE DIFFERENCE IS!" question.
Save your breath Steve. You got no joy before and none will be had here. Others have brick-walled as you do. It is patently (no pun...) obvious to me and I think to all reasonable forum browsers who understands what and who can fill a hot-air balloon while dancing with Ginger Rogers. Push the issue and you're likely to get a "middle finger" or be called a "moron". Isn't that how it works, Frank?
:headshot: |
|
|
| kuribo |
"Time for you to come out of the cupboard and 'splain it to the more brilliant minds.
Mind you, you don't have to and I'm not actually demanding anything from you unlike some somewhat lesser gods. Oopsie.
Again, spot the difference?"
We all spot the difference...Steve is trying to understand. You are playing games.
Why on earth would you ask me to explain something YOU said? What are ya, nuts?
Either you can't explain, or you don't want to. In either case, you are wasting this forum's space and time...So run along Master and bait somewhere else.... |
|
|
| Steve Eddy |
| quote: | Originally posted by kuribo
I think everyone has noticed the difference, that being that you made a claim (DA and DH are different), and Steve asked you to explain the difference. Quite a fair request. You have yet to explain this difference, rather you hide behind mumbo-jumbo, and bait Steve. At that you are a true master. |
Hmmmm. Didn't I see this somewhere before already? :)
se |
|
|
| janneman |
| quote: | Originally posted by Christer
To late to add to previous post by editing.
Jan,
I have just reread, alhthough quickly, all what I wrote in this
thread, and all that you wrote to, BTW, and I am even more
puzzled what you might be referring to. Since you lumped
me, John and Frank together but left, for instance, Steve out,
you seem to think I have made some claim in agreement
with Frank and John and which is wrong, while at the same
time it seems you agree with Steve. I cannot see I have made
any such claims. However, you have made claims that I intepret
as agreeing with Frank and John while not agreeing with Steve.
This is really puzzling. Maybe I am confusing you by not taking
a clear stand and claim anything at all? you see, I don't want
to make claims about whether a certain pehnomenon exists
or not without having evidence of it, as some people inlcuding
you seem not to mind.
Jan, I beg you for a clarification of what you "accused" me of,
either here or by email. I don't wan't to be accused of
making errors without getting a chance to either admit it
or clarify myself. |
Christer,
I wrote my post yesterday evening, frustrated and disappointed that the bulk of the other posters kept on saying: "no, you don't know it. I know, but I won't tell you where I found it" and more of those essentially content free ramblings. I apologize for including you instead of SE; you did more than your share in trying to save threads and discussions. And I know I haven't contributed to this thread; but am I not entitled to learn something once in a while? But it won't be from this thread.
It is now 12 hours and several pages (!) of posts later, and it goes on and on and on. Amazing!
It does give you a small peek into human behaviour that can lead to nasty inter-tribal atrocities. Be happy that internet doesn't (yet) forward bombs and bullets.
Jan Didden |
|
|
| Steve Eddy |
| quote: | Originally posted by janneman
I apologize for including you instead of SE; |
What, you mean Christer's out and I'm in?
Thanks a lot, Christer! TATTLETALE! :D
se |
|
|
| Christer |
Jan,
your apology is accepted.
I also agree that the tread is losing more and more focus
and becoming more and more confused. It reminds me a
bit if that Bach kantata with soparano and tenor singing
"Ach ja, ach nein, ach ja, ach nein ..." ad infinitum. My only
reason, except for a general curiosity to learn a bit more
about things, has been to try steer up the discussion by
pointing to things that need to be cleared up and that needs
to be backed up by better arguments etc. if the thread is
to progress at all. I am sure not everybody sees it that
way and I may have failed in my "mission" and just caused
more confusion. |
|
|
| Christer |
| quote: | Originally posted by fdegrove
Like I, Bob Pease style, would say, let's not find problems but solve problems: DH is not likely to occur in filmcaps or any half-decent audio cables.
|
Aha, are we finally getting somewhere? So perhaps DH is then
a phenomenon only in ceramics, electrolytics and other "strange"
caps, which we already know are more complex to model than
film caps?
Couldn't you have said so some three or four hundred pages
ago??? ;) |
|
|
| IanHarvey |
Forgive me, but the phrase "linear distortion" seems even more of a contradiction in terms than "military intelligence".
"Linear distortion", or whatever it is you want to call it, only has effects which are measurable using continuous sinewaves.
I hereby sneer publicly at anybody who claims "linear distortion" in cables is worth worrying about, until they publish a genuine measured frequency response plot of their loudspeakers in their listening room. That's the sort of "linear distortion" you're up against.
If you've not done this - buy a good soundcard, buy AudioTester, buy a good reference microphone, and just do it. If you're not ashamed and embarrassed to publish the results, I look forward to seeing them....
Cheers
IH |
|
|
| Steve Eddy |
| quote: | Originally posted by Christer
Aha, are we finally getting somewhere? So perhaps DH is then
a phenomenon only in ceramics, electrolytics and other "strange"
caps, which we already know are more complex to model than
film caps? |
Hmmmm. Why wouldn't it occur in film caps? DA is hysteretic, yes? From what I've seen so far, it seems that dielectric hysteresis currently the preferred terminology when it comes to ferroelectric materials. The only difference I seem to have found is that the mechanisms are different. In typical plastic dielectrics, it's due to polar molecules while in ferroelectric ceramics it's due to electric domains.
se |
|
|
| Steve Eddy |
| quote: | Originally posted by IanHarvey
Forgive me, but the phrase "linear distortion" seems even more of a contradiction in terms than "military intelligence". |
At first glance it would seem so. But seeing as "linear distortion" is an alteration of the waveform, I don't see that it's any less a distortion than nonlinear distortion.
| quote: | | "Linear distortion", or whatever it is you want to call it, only has effects which are measurable using continuous sinewaves. |
How do you figure?
| quote: | | I hereby sneer publicly at anybody who claims "linear distortion" in cables is worth worrying about, until they publish a genuine measured frequency response plot of their loudspeakers in their listening room. That's the sort of "linear distortion" you're up against. |
Not to mention a considerable amount of non-linear distortion as well, particularly IM.
se |
|
|
| SY |
| Again, in plastic film caps, the DA is generally not due to the dipole moment of the molecules; it's a function of charge storage in polarizable regions. A smaller effect than dipole alignment to be sure, but that's why plastic film caps have orders of magnitude lower DA than electrolytics and some types of ceramics. The dipole moments are essentially tied down because they're part of long chains which can't wiggle around much below the plastic's Tg. |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Again, in plastic film caps, the DA is generally not due to the dipole moment of the molecules; it's a function of charge storage in polarizable regions. |
Ok, so the Kundert paper's erroneous on that count? Do you have a source for what you say is the actual cause?
se |
|
|
| SY |
Kundert's paper is a way to model DA for materials in general. Trying to extrapolate it to understand specific physical mechanisms in specific families of materials is stretching it farther than the author intended. Note that the author doesn't show any diagrammatic representation of a polymer containing a dipole moment, doesn't deal with specific mechanisms of induced polarizability or charge stabilization, nor define what he means by "dipole" or "charge particle" in a molecular sense. That's not a defect of the paper, it's just something beyond its scope.
There are a few hundred books out there on the electrical properties of polymers. I may have even contributed to a few of them. I'm not at my office today, but my next time there (probably Monday), I'll suggest a title or two. |
|
|
| Christer |
| quote: | Originally posted by Steve Eddy
Hmmmm. Why wouldn't it occur in film caps? DA is hysteretic, yes? From what I've seen so far, it seems that dielectric hysteresis currently the preferred terminology when it comes to ferroelectric materials. The only difference I seem to have found is that the mechanisms are different. In typical plastic dielectrics, it's due to polar molecules while in ferroelectric ceramics it's due to electric domains.
se |
Maybe I was unclear. The comment was made under
the assumption that Frank is right that DA and DH are
different phenomenae. My earlier impression of his claims was
that both always exst in parallel (jumping to conclusions
perhaps, but a reasonable one given how little he told us,
I think). Since for instance ceramic caps have a non-linear
behaviour not present in film caps and certain other strange
behaviours, it now seemed more plausible to me that there might,
perhaps, be some further hysetersis phenomenen besides
DA in them. If it is so, I have no idea. Maybe SY has something
to say, he seems to know this stuff on detailed level, but
maybe it is only polymers he knows about? |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
Kundert's paper is a way to model DA for materials in general. Trying to extrapolate it to understand specific physical mechanisms in specific families of materials is stretching it farther than the author intended. Note that the author doesn't show any diagrammatic representation of a polymer containing a dipole moment, doesn't deal with specific mechanisms of induced polarizability or charge stabilization, nor define what he means by "dipole" or "charge particle" in a molecular sense. That's not a defect of the paper, it's just something beyond its scope. |
Ok.
| quote: | | There are a few hundred books out there on the electrical properties of polymers. I may have even contributed to a few of them. |
Ok, if you so smart, who wunnuh secon whurl whoa? :D
| quote: | | I'm not at my office today, but my next time there (probably Monday), I'll suggest a title or two. |
Thanks. In the meantime, how 'bout some keywords that might be searched on the net?
se |
|
|
| SY |
| quote: | | Ok, if you so smart, who wunnuh secon whurl whoa? |
"Not responsible!"
I'd search "polymer charge storage" to start.
| quote: | | Maybe SY has something |
I'm still waiting for someone to define their terms. I understand what DA is about, and it exhibits the properties of a hysteretic phenomenon. But I have no idea what the people who are claiming that DH is something distinct mean by the terms they're using. I'm just an ignorant materials scientist. |
|
|
| Steve Eddy |
| quote: | Originally posted by Christer
Maybe I was unclear. The comment was made under
the assumption that Frank is right that DA and DH are
different phenomenae. My earlier impression of his claims was
that both always exst in parallel (jumping to conclusions
perhaps, but a reasonable one given how little he told us,
I think). Since for instance ceramic caps have a non-linear
behaviour not present in film caps and certain other strange
behaviours, it now seemed more plausible to me that there might,
perhaps, be some further hysetersis phenomenen besides
DA in them. If it is so, I have no idea. |
Well, I'm wondering if the nonlinearities in ferroelectrics, which seem to behave anaogously to ferromagnetics may be due to an equivalent "saturation" that you find in ferromagnetics.
| quote: | | Maybe SY has something to say, he seems to know this stuff on detailed level, but maybe it is only polymers he knows about? |
Perhaps. I'm willing to listen to all parties as long as they have something to say other than "they're different." :)
se |
|
|
| Steve Eddy |
| quote: | Originally posted by SY
I'd search "polymer charge storage" to start. |
Thanks.
| quote: | | I'm still waiting for someone to define their terms. I understand what DA is about, and it exhibits the properties of a hysteretic phenomenon. But I have no idea what the people who are claiming that DH is something distinct mean by the terms they're using. |
Dunno about you, but I ain't holdin' my breath on that one. :)
| quote: | | I'm just an ignorant materials scientist. |
So would that make you a *ahem* mat' scientist? :)
se |
|
|
| Fred Dieckmann |
" Thanks. In the meantime, how 'bout some keywords that might be searched on the net?"
Try:
LUNATIC
MONOMANIA
ACOETHES
LOGOMANIA
PREPOSSESSION
You guys keep him distracted with Dielectric Hysteresis:hypno2:while I sneak up behind him:shhh: and throw the net over him, and knock him out.... :trapper: :crackup: :smash: :cop: :judge: :lock:
Fred
PS
:att'n: "Although stalking victims may desperately want to know why they were chosen as the victim, what they might have done to trigger a stalker's obsession with them, often, they find the answer is NOTHING. They are just one of a serial stalker's many victims. These stalkers are simply following a pattern of behaviour they have practised for years. No matter what the reason or cause for the stalking, victims should be cautioned that serial stalkers in particular are very disturbed individuals.":yes: |
|
|
| fdegrove |
Hi,
| quote: | | You guys keep him distracted with Dielectric Hysteresiswhile I sneak up behind him and throw the net over him, and knock him out.... |
Whoah......Now I'm really hysterical....:clown:
Cheers,;) |
|
|
| fdegrove |
Hi,
| quote: | | Either you can't explain, or you don't want to. In either case, you are wasting this forum's space and time...So run along Master and bait somewhere else.... |
As a matter of fact, I have explained it already but it turned out the explanation was either not convenient or just too damn simple to be accepted.
So, what about who's wasting space where? And who's baiting who?
If you don't care to read through the entire thread than that's your choice, just don't blame me for your choices.
For your convenience I'll repeat it once more:
DH is a consequence of DA under some circumstances, DA and DH are not the same. No matter how many publications confuse both.
If you want proof of it do some research on integrator techniques.
In the meantime just be nice to animals like myself, please.
Cheers,;) |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
As a matter of fact, I have explained it already but it turned out the explanation was either not convenient or just too damn simple to be accepted. |
I must've missed it. Did you write it in disappearing ink?
| quote: | For your convenience I'll repeat it once more:
DH is a consequence of DA under some circumstances, DA and DH are not the same. No matter how many publications confuse both. |
That's an explanation? Gee, could you make it just a little more vague?
explain 1 a L to make known b : to make plain or understandable 2 : to give the reason for or cause of 3 : to show the logical development or relationships of : to make something plain or understandable.
But as far as your "explanation" goes, what circumstances is DH a consequence of DA and what circumstances is it not? If DA is inherently hysteretic, when can DH not be a consequence of DA?
| quote: | | If you want proof of it do some research on integrator techniques. |
If I Google "dielectric hysteresis" and "integrator" I come up with just 5 hits. Only one is of any relevance.
http://dsp.hit.edu.cn/graduates/doc...xiaodan/ADC.pdf
This paper presents a new method of A/D conversion based on width modulating circuit. Its state of working is so steady that it hasn't nonlinear error in theory and can omit the dielectric hysteresis effect of integral capacitor.
Now if I Google "dielectric absorption" and "integrator" I get 183 hits, the first of which is Pease's piece on "soakage." As well as a bunch of others along similar lines.
And if I do a search on "dielectric absorption" and "integrator" and "hysteresis" I get some interesting results. Such as this datasheet for some National monolithic sample and hold circuits:
http://www.ee.washington.edu/stores...inear/lf398.pdf
A significant source of error in an accurate sample and hold circuit is dielectric absorption in the hold capacitor. A mylar cap, for instance, may "sag back" up to 0.2% after a quick change in voltage. A long sample time is required before the circuit can be put back into the hold mode with this type of capacitor. Dielectrics with very low hysteresis are polystyrene, polypropylene, and Teflon. Other types such as mica and polycarbonate are not nearly as good. The advantage of polypropylene over polystyrene is that it extends the maximum ambient temperature from 85C to 100C. Most ceramic capacitors are unusable with > 1% hysteresis. Ceramic "NPO" and "COG" capacitors are now available for 125C operation and also have low dielectric absorption. For more exact data, see the curve Dielectric Absorption Error. The hysteresis numbers are final values, taken after full relaxation. The hysteresis error can be significantly reduced if the output of the LF198 is digitized quickly after the hold mode is initiated. The hysteresis relaxation time constant in polypropylene, for instance, is 10-50 ms. If A-to-D conversion can be made within 1 ms, hysteresis error will be reduced by a factor of 10.
So, is National confusing both here?
se |
|
|
| fdegrove |
Hi,
| quote: | | That's an explanation? Gee, could you make it just a little more vague? |
It is and I couldn't make it anymore clearer than it already is....
Lest you want to look up what hysteresis is and what DA means there's very little to say about it...
Unless you want to go way beyond audio use that is perhaps.
Once again, DH is and can be an artefact of DA.
DH and DA are NOT the same, no matter how much nonsense you may dig up on the net.
To understand it you need to know the difference between the two.
So, here we go again, ad nauseam et ad bored to death dom....
Cheers, |
|
|
| Steve Eddy |
| quote: | Originally posted by fdegrove
It is and I couldn't make it anymore clearer than it already is....
Lest you want to look up what hysteresis is and what DA means there's very little to say about it... |
Ok, let's start with hysteresis:
The magnetization of ferromagnetic substances due to a varying magnetic field lags behind the field. This effect is called hysteresis, and the term is used to describe any system in whose response depends not only on its current state, but also upon its past history.
hys-ter-e-sis:
n [NL, fr. Gk hysteresis shortcoming, fr. hysterein to be late, fall short, fr. hysteros later]
a retardation of the effect when the forces acting upon a body are changed (as if from viscosity or internal friction); esp: a lagging in the values of resulting magnetization in a magnetic material (as iron) due to a changing magnetizing force. -hys-ter-et-ic adj
The lagging of an effect behind its cause, as when the change in magnetism of a body lags behind changes in the magnetic field.
HYSTERESIS (Gr. iIaT~p~OTI, from ior~piv, to lag behind), a term added to the vocabulary of physical science by J. A. Ewing, who defines it as follows: When there are two qualities M and N such that cyclic variations of N cause cyclic variations of M, then if the changes of M lag behind those of N, we may say that there is hysteresis in the relation of M to N (Phil. Trans., 1885, 176, p. 524).
Now dielectric absorption:
A capacitor which has been charged for a long time and then been completely discharged, has a small voltage on its terminal wires again, within seconds or minutes.
This effect is known as dielectric absorption.
This is the phenomenon where after a capacitor has been charged for some time, and then discharged, some stored charge will migrate out of the dielectric over time, thus changing the voltage value of the capacitor.
A characteristic of dielectrics which determines the length of time a capacitor takes to deliver the total amount of its stored energy. It manifests itself as the reappearance of a potential on the electrodes after the capacitor has been discharged. Its magnitude depends on the charge and discharge time of the capacitor.
Ok. Now what?
| quote: | | Once again, DH is and can be an artefact of DA. |
Ok, again, when is it that DH isn't an artefact of DA?
se |
|
|
| fdegrove |
Hi,
| quote: | | The magnetization of ferromagnetic substances due to a varying magnetic field lags behind the field. This effect is called hysteresis, and the term is used to describe any system in whose response depends not only on its current state, but also upon its past history. |
That's ferroelectrics in the first place and shows that DH can take place in ferromagnetic materials.
Now, where's does this come up in filmcaps or cables?
Cables and filmcaps do have DA but where's the DH?
You just keep on dragging in proof of what I keep claiming.
Cheers,;) |
|
|
| Pjotr |
Please can someone throw in a fresh bone in here?
It would be interesting if someone can repeat the distortion profile of a cable as showed by John, preferable completely independent. Up to then quibbling about DH/DA/hysteresis looks pretty valueless with regard to cables.
If nobody can, what is this whole discussion about :confused:
Cheers |
|
|
| johnferrier |
| quote: | Originally posted by Pjotr
If nobody can, what is this whole discussion about :confused: |
This is a discussion about possible distorting elements in cables. It started out with cable microdiodes: fact or fiction? And turned into: capacitance dielectric hysteresis something other than dielectric absorption?
Unless someone provides supporting material, I don't expect we'll learn anything about cables until we see results of the directionality test.
Thus far, SE has cleared the unsupporting material.
JF |
|
|
|
