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.
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.
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.
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.
Hi,
Got it, no or little heating to release electrons.
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,😉
Got it, no or little heating to release electrons.
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,😉
Hi,
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,
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,
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.
The time lag that you speak of is fantastically small, which is why polyethylene has low losses up to ridiculously high frequencies.
fdegrove said:
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.
No, you are your own employee working in the service of substantiating your own claims, which is your responsibility, not mine.
10 references per page? Damn, Frank, make life easier on yourself and go to Preferences and set it for 100 per page.
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.
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?
Not one but me? Did you miss the FaradNet glossary reference for dielectric absorption?
Also called dielectric hysteresis or dielectric soak.
se
SY said:
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.
Attachments
john curl said:
You might want to give Kundert's paper a read:
http://www.designers-guide.com/Modeling/da.pdf
In the time domain, John. It will affect frequency and phase resopnse.
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:
An externally hosted image should be here but it was not working when we last tested it.
se
Hi,
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.
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,😉
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.
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,😉
fdegrove said:
Then stop dancing around like Fred Astaire tell us all what the difference is, Frank.
se
Hi,
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,😉
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,😉
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.
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 said:
Who said anything about the model, Frank?
JUST EXPLAIN WHAT THE DIFFERENCE IS!
Again, who said anything about the model?
JUST EXPLAIN WHAT THE DIFFERENCE IS!
Yet again, who said anything about the model?
Those who can think can explain. Those who can't just dance.
se
Attachments
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.
WAIT A MINUTE....
Hi,
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?
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,😉
Hi,
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?
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,😉
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?
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?
"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....
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....
Christer said:
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
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