[NoSPAM]

"Ian Bell" wrote in message
...
Ian Iveson wrote:
Ian Bell wrote :

Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.


I wonder, if film is film, what the difference is?

And, if an 85C cap is operated at 105C, which quoted electrical parameter
is no longer valid?

Ian



Well they all seem to use a PET film and as someone else pointed out there
are relatively few suppliers of such films. I think the construction may
have something to do with it. Certainly there are non-inductive and
regular (presumably inductive) methods of construction which will have a
bearing on the price although all the ones I have looked at so far seem to
be of the non-inductive type.

As far as temperature rating is concerned, WIMA say to derate the voltage
rating by 1.25% per degree from 85 degrees for dec voltages and from 75
degrees for the ac voltage rating. I have not seen deratings given by
other manufacturers so far.

Cheers

Ian

The glass transition temperature for polyethylene terephthalate (PET) is
around 90 to 96 C. Lots of things happen at the temperature including
dimensional changes, dielectric constant, etc. To get to higher
temperatures, glycol modified polyesters (PETG) are sometimes used. Another
polyester, polyethylene naphthalate (PEN), is another possibility for higher
temperatures. PEN capacitors are often used for switching supply filters at
high temperatures.

Dr. Barry L. Ornitz WA4VZQ

[Eeyore]

Ian Bell wrote:

Ian Iveson wrote:
Ian Bell wrote :

Thank you, that us useful information. I have been
checking data sheets and I notice that the WIMA parts are
rated to operate up to 105 degrees C where as the others
only to 85 degrees. Perhaps that explains why the WIMA
parts are a little more expensive.

I wonder, if film is film, what the difference is?

And, if an 85C cap is operated at 105C, which quoted
electrical parameter is no longer valid?

Well they all seem to use a PET film and as someone else pointed out
there are relatively few suppliers of such films. I think the
construction may have something to do with it. Certainly there are
non-inductive and regular (presumably inductive) methods of construction
which will have a bearing on the price although all the ones I have
looked at so far seem to be of the non-inductive type.

As far as temperature rating is concerned, WIMA say to derate the
voltage rating by 1.25% per degree from 85 degrees for dec voltages and
from 75 degrees for the ac voltage rating. I have not seen deratings
given by other manufacturers so far.

That is typical WIMA thoroughness, it has to be said. Although I can't think
of a reason for it.

Graham

[Ian Bell[_2_]]

Eeyore wrote:

Ian Bell wrote:

Mikkel C. Simonsen wrote:
Ian Bell wrote:
When I ordered a large(ish) quantity of caps last year I compared the
prices from many sources. In all cases but one specific type/value Wima
was more expensive than the competition. Farnell prices are always very
high - I order from the factory directly or from a distributor.

Interesting, especially as you are in Europe like me. Can you be a bit
more specific about what you mean by 'largish' quantities?
In this case between 50 and 500 pieces per value.
Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

On polyester caps ?

Graham


Sorry what are you querying? that they are more expensive? (than other
polyester caps) - there is some evidence that they are - or that they
are rated to operate up to 105 degrees? - the WIMA data sheet says so.

Cheers

ian

[Eeyore]

Ian Bell wrote:

Eeyore wrote:
Ian Bell wrote:
Mikkel C. Simonsen wrote:
Ian Bell wrote:
When I ordered a large(ish) quantity of caps last year I compared the
prices from many sources. In all cases but one specific type/value Wima
was more expensive than the competition. Farnell prices are always very
high - I order from the factory directly or from a distributor.

Interesting, especially as you are in Europe like me. Can you be a bit
more specific about what you mean by 'largish' quantities?
In this case between 50 and 500 pieces per value.
Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

On polyester caps ?


Sorry what are you querying? that they are more expensive? (than other
polyester caps) - there is some evidence that they are - or that they
are rated to operate up to 105 degrees? - the WIMA data sheet says so.

Puzzled at the different temp ratings.

Graham

[Mikkel C. Simonsen]

Ian Bell wrote:

Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

The "cheap" caps I use are rated for either 100°C or 110°C

Best regards,

Mikkel C. Simonsen

[Ian Iveson]

NoSPAM wrote

The glass transition temperature for polyethylene
terephthalate (PET) is around 90 to 96 C. Lots of things
happen at the temperature including dimensional changes,
dielectric constant, etc. To get to higher temperatures,
glycol modified polyesters (PETG) are sometimes used.
Another polyester, polyethylene naphthalate (PEN), is
another possibility for higher temperatures. PEN
capacitors are often used for switching supply filters at
high temperatures.

Thanks for that.

I wonder if PET caps are wound when warm.

And, considering the Tg of polypropylene is much lower, I
wonder what its significance is for a capacitor in this kind
of application.

Ian

[Eeyore]

Ian Iveson wrote:

And, considering the Tg of polypropylene is much lower

Tg ? Tigger ? BOUNCE BOUNCE !

Graham

[Ian Bell[_2_]]

Mikkel C. Simonsen wrote:
Ian Bell wrote:
Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

The "cheap" caps I use are rated for either 100°C or 110°C

Best regards,

Mikkel C. Simonsen


Who makes these 'cheap' caps?

Cheers

Ian

[Mikkel C. Simonsen]

Ian Bell wrote:

Mikkel C. Simonsen wrote:
Ian Bell wrote:
Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

The "cheap" caps I use are rated for either 100°C or 110°C

Best regards,

Mikkel C. Simonsen

Who makes these 'cheap' caps?

Electel in Germany, as I think I have written in a previous post.

Best regards,

Mikkel C. Simonsen

[Eeyore]

"Mikkel C. Simonsen" wrote:

Ian Bell wrote:

Mikkel C. Simonsen wrote:
Ian Bell wrote:
Thank you, that us useful information. I have been checking data sheets
and I notice that the WIMA parts are rated to operate up to 105 degrees
C where as the others only to 85 degrees. Perhaps that explains why the
WIMA parts are a little more expensive.

The "cheap" caps I use are rated for either 100°C or 110°C

Best regards,

Mikkel C. Simonsen

Who makes these 'cheap' caps?

Electel in Germany, as I think I have written in a previous post.

And do any of you SERIOUSLY think they use different films ?

Graham

[Ian Iveson]

Eeyore wrote:

And, considering the Tg of polypropylene is much lower

Tg ? Tigger ? BOUNCE BOUNCE !

Er...eh?

Tg is the glass transition temperature, at which a polymer
changes from stiff and brittle to plastic and tough. At some
higher temperature it starts getting squidgy, and flows
under low pressure. At some even higher temperature, you
might say it's melted. My experience with household items
made of polycarbonate suggests that the difference between
Tg and melted is not very great, whereas polythene seems to
stay plastic over a wide range.

We tend to take plastics for granted without always
realising how various they are, how complex they can be, and
how they are tailored for specific purposes. I remember when
plastic kettles were introduced, and no-one seemed to wonder
why they don't soften or melt even if you forget to put
water in.

Considering the poster to whom I replied was writing about
the glass transition temperature, I didn't think I would
need to explain Tg.

Ian

[Eeyore]

Ian Iveson wrote:

Eeyore wrote:

And, considering the Tg of polypropylene is much lower

Tg ? Tigger ? BOUNCE BOUNCE !

Er...eh?

Tg is the glass transition temperature, at which a polymer
changes from stiff and brittle to plastic and tough. At some
higher temperature it starts getting squidgy, and flows
under low pressure. At some even higher temperature, you
might say it's melted. My experience with household items
made of polycarbonate suggests that the difference between
Tg and melted is not very great, whereas polythene seems to
stay plastic over a wide range.

We tend to take plastics for granted without always
realising how various they are, how complex they can be, and
how they are tailored for specific purposes. I remember when
plastic kettles were introduced, and no-one seemed to wonder
why they don't soften or melt even if you forget to put
water in.

Considering the poster to whom I replied was writing about
the glass transition temperature, I didn't think I would
need to explain Tg.

I realised what you were saying actually but I fail to see how one
plastic made by manufacturer X should have a significantly different
glass transistion temp from the same plastic made by manufacturer Y.

Polypropylene's still damn good stuff btw with low DA.

Grahm

[Rudy]

"Eeyore" wrote in message
...
:
:
: "Mikkel C. Simonsen" wrote:
:
: Ian Bell wrote:
:
: Mikkel C. Simonsen wrote:
: Ian Bell wrote:
: Thank you, that us useful information. I have been checking data sheets
: and I notice that the WIMA parts are rated to operate up to 105 degrees
: C where as the others only to 85 degrees. Perhaps that explains why the
: WIMA parts are a little more expensive.
:
: The "cheap" caps I use are rated for either 100°C or 110°C
:
: Best regards,
:
: Mikkel C. Simonsen
:
: Who makes these 'cheap' caps?
:
: Electel in Germany, as I think I have written in a previous post.
:
: And do any of you SERIOUSLY think they use different films ?
:
: Graham

"The electrodes 12, 18 typically comprise metal foils. In one embodiment, the electrodes
12, 18 comprise at least one of aluminum, copper, or zinc foil. The first dielectric layer
14 typically comprises an organic polymer, an inorganic material or a polymer film. A
non-limiting example of an inorganic material is boron nitride (BN), mica, paper, silicon
nitride (Si 3 N 4 ) or aluminum nitride (AIN). Some non-limiting examples of a polymer
film include polypropylene (PP), polyester (PET), polyphenylene sulfide (PPS),
polycarbonate (PC), fluorenyl polester (FPE), polyetheretherketon (PEEK), polyethersulfone
(PES), polyvinylidene fluoride (PVDF), polyimide, polyamide-imide, teflon
(polytetrafluoroethelyne) (PTFE), polyvinylidene fluoride (PVDF-TrFE), Ultem®
(polyetherimide) and combinations thereof. The second dielectric layer 16 may comprise an
organic polymer, an inorganic material or polymer composite film. A non-limiting example
of an inorganic material is boron nitride (BN), alumina (Al 2 O 3 ), silica (SiO 2 ),
titania (TiO 2 ), aluminium nitride (AIN) and silicon nitride (Si 3 N 4 ). Some
non-limiting examples of the polymer film used as second dielectric layer include
polyethylene phthalate (PET), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF).
Some non-limiting examples of polymer composites comprising inorganic material or polymer
can be Ultem® polyetherimide, PP, PET, PVDF, FPE, PEEK, PES, PC or PPS containing BN, Al 2
O 3 , SiO 2 , TiO 2 , Niobium pentoxide (Nb 2 O 5 ), Tantalum pentoxide (Ta 2 O 5 ) and
combinations thereof. In a non-limiting example, the thickness of the second dielectric
layer is in the range between about 0.3 microns to about 5 microns. A non-limiting example
of a first dielectric constant is at least about 2. In a non-limiting example, the second
dielectric constant is in the range between 3 and 100."

from:
http://www.freepatentsonline.com/EP1786006.html
;-)

[Eeyore]

Rudy wrote:

"Eeyore" wrote
: "Mikkel C. Simonsen" wrote:
: Ian Bell wrote:
: Mikkel C. Simonsen wrote:
: Ian Bell wrote:
: Thank you, that us useful information. I have been checking data sheets
: and I notice that the WIMA parts are rated to operate up to 105 degrees
: C where as the others only to 85 degrees. Perhaps that explains why the
: WIMA parts are a little more expensive.
:
: The "cheap" caps I use are rated for either 100°C or 110°C
:
: Best regards,
:
: Mikkel C. Simonsen
:
: Who makes these 'cheap' caps?
:
: Electel in Germany, as I think I have written in a previous post.
:
: And do any of you SERIOUSLY think they use different films ?
:
: Graham

"The electrodes 12, 18 typically comprise metal foils. In one embodiment, the electrodes
12, 18 comprise at least one of aluminum, copper, or zinc foil. The first dielectric layer
14 typically comprises an organic polymer, an inorganic material or a polymer film. A
non-limiting example of an inorganic material is boron nitride (BN), mica, paper, silicon
nitride (Si 3 N 4 ) or aluminum nitride (AIN). Some non-limiting examples of a polymer
film include polypropylene (PP), polyester (PET), polyphenylene sulfide (PPS),
polycarbonate (PC), fluorenyl polester (FPE), polyetheretherketon (PEEK), polyethersulfone
(PES), polyvinylidene fluoride (PVDF), polyimide, polyamide-imide, teflon
(polytetrafluoroethelyne) (PTFE), polyvinylidene fluoride (PVDF-TrFE), Ultem®
(polyetherimide) and combinations thereof. The second dielectric layer 16 may comprise an
organic polymer, an inorganic material or polymer composite film. A non-limiting example
of an inorganic material is boron nitride (BN), alumina (Al 2 O 3 ), silica (SiO 2 ),
titania (TiO 2 ), aluminium nitride (AIN) and silicon nitride (Si 3 N 4 ). Some
non-limiting examples of the polymer film used as second dielectric layer include
polyethylene phthalate (PET), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF).
Some non-limiting examples of polymer composites comprising inorganic material or polymer
can be Ultem® polyetherimide, PP, PET, PVDF, FPE, PEEK, PES, PC or PPS containing BN, Al 2
O 3 , SiO 2 , TiO 2 , Niobium pentoxide (Nb 2 O 5 ), Tantalum pentoxide (Ta 2 O 5 ) and
combinations thereof. In a non-limiting example, the thickness of the second dielectric
layer is in the range between about 0.3 microns to about 5 microns. A non-limiting example
of a first dielectric constant is at least about 2. In a non-limiting example, the second
dielectric constant is in the range between 3 and 100."

from:
http://www.freepatentsonline.com/EP1786006.html

The films you mention are indeed different. That was not at dispute. What was at dispute was
whether a film of a certain chemical composition varies from manufacturer X to manufacturer Y.

Graham

[Ian Iveson]

Eeyore wrote

And, considering the Tg of polypropylene is much lower

Tg ? Tigger ? BOUNCE BOUNCE !

Er...eh?

Tg is the glass transition temperature, at which a
polymer
changes from stiff and brittle to plastic and tough. At
some
higher temperature it starts getting squidgy, and flows
under low pressure. At some even higher temperature, you
might say it's melted. My experience with household items
made of polycarbonate suggests that the difference
between
Tg and melted is not very great, whereas polythene seems
to
stay plastic over a wide range.

We tend to take plastics for granted without always
realising how various they are, how complex they can be,
and
how they are tailored for specific purposes. I remember
when
plastic kettles were introduced, and no-one seemed to
wonder
why they don't soften or melt even if you forget to put
water in.

Considering the poster to whom I replied was writing
about
the glass transition temperature, I didn't think I would
need to explain Tg.

I realised what you were saying actually but I fail to see
how one
plastic made by manufacturer X should have a significantly
different
glass transistion temp from the same plastic made by
manufacturer Y.

Same plastic? You are tricking yourself with logical
chicanery. One point I am making is that there are many
forms and qualities of PET. One PET is therefore not "the
same" as another.

You have also confused yourself with respect to the variety
of manufacturers. First you said that there are only a very
few producers, implying that variety in PET film might be
proportional to the variety in manufacturers. Now you appear
to be arguing that there is no difference, regardless of
manufacturer, in which case it wouldn't matter how many
different manufacturers there are.

In any event, you are quite wrong.

Considering all the complications of PET film manufacture,
and the range of possible outcomes of all the processes
involved, it is incumbent upon you to demonstrate that the
PET used for capacitor dielectrics is always the same.

In particular, in keeping with this sub-thread, why does the
temperature rating of PET caps vary?

I was questioning the significance of Tg, considering that
PET is rigid at room temp, whereas polypropylene is plastic.
Further, if the Tg of PET is around 90C, and all PETs are
the same, then the dielectric of a 105C PET cap can pass
through its Tg and still meet its spec.

I suggest you look it up. I can give you a couple of clues:
chain length (average and SD), and orientation. You should
look for boPET.

Here is an obvious starter

http://en.wikipedia.org/wiki/PET_fil...ially_oriented)

Polypropylene's still damn good stuff btw with low DA.

As I said earlier. C0G ceramics are excellent too, as is
polystyrene. Other common plastic dielectrics, including
metalised PET, are inferior with respect to signal
distortion, although the significance of the difference may
reasonably be doubted.

Film storage and quality of encapsulation are other
significant variables, considering that PET, for example, is
hydroscopic.

Ian

[Rudy]

"Eeyore" wrote in message
...
:
:
: Rudy wrote:
:
: "Eeyore" wrote
sn :
: : And do any of you SERIOUSLY think they use different films ?
: :
: : Graham
:
: "The electrodes 12, 18 typically comprise metal foils. In one embodiment, the
electrodes
: 12, 18 comprise at least one of aluminum, copper, or zinc foil. The first dielectric
layer
: 14 typically comprises an organic polymer, an inorganic material or a polymer film. A
: non-limiting example of an inorganic material is boron nitride (BN), mica, paper,
silicon
: nitride (Si 3 N 4 ) or aluminum nitride (AIN). Some non-limiting examples of a polymer
: film include polypropylene (PP), polyester (PET), polyphenylene sulfide (PPS),
: polycarbonate (PC), fluorenyl polester (FPE), polyetheretherketon (PEEK),
polyethersulfone
: (PES), polyvinylidene fluoride (PVDF), polyimide, polyamide-imide, teflon
: (polytetrafluoroethelyne) (PTFE), polyvinylidene fluoride (PVDF-TrFE), Ultem®
: (polyetherimide) and combinations thereof. The second dielectric layer 16 may comprise
an
: organic polymer, an inorganic material or polymer composite film. A non-limiting
example
: of an inorganic material is boron nitride (BN), alumina (Al 2 O 3 ), silica (SiO 2 ),
: titania (TiO 2 ), aluminium nitride (AIN) and silicon nitride (Si 3 N 4 ). Some
: non-limiting examples of the polymer film used as second dielectric layer include
: polyethylene phthalate (PET), polyphenylene sulfide (PPS), polyvinylidene fluoride
(PVDF).
: Some non-limiting examples of polymer composites comprising inorganic material or
polymer
: can be Ultem® polyetherimide, PP, PET, PVDF, FPE, PEEK, PES, PC or PPS containing BN,
Al 2
: O 3 , SiO 2 , TiO 2 , Niobium pentoxide (Nb 2 O 5 ), Tantalum pentoxide (Ta 2 O 5 )
and
: combinations thereof. In a non-limiting example, the thickness of the second
dielectric
: layer is in the range between about 0.3 microns to about 5 microns. A non-limiting
example
: of a first dielectric constant is at least about 2. In a non-limiting example, the
second
: dielectric constant is in the range between 3 and 100."
:
: from:
: http://www.freepatentsonline.com/EP1786006.html
:
: The films you mention are indeed different. That was not at dispute. What was at dispute
was
: whether a film of a certain chemical composition varies from manufacturer X to
manufacturer Y.
:
: Graham
:
true. but from the above, i'd infer that capacitor manufacturers can pretty much specify
the composition and thickness, uniformity of film, so it seems quite likely different
manufacturers
will use different film/thickness/uniformity/mechanical process to manufacture the
capacitors,
undoubtedly giving different electrical and mechanical/dampness resistance/aging, etc.
characteristics.

whether it effects the signal, when used as a coupling cap, is another matter,
an interesting test would be a Belcher test, with continuous quasi-random noise
applied and the total IM products thus measured would be far more indicative
of what you can expect with musical signals than a standard 2 tone IM test.

see for a description here, page 101-103, section 3.12.3:
http://www.enigma-systems.de/manuals...promanuale.pdf

Rudy

[Arny Krueger]

"Rudy" wrote in message
b.home.nl...

whether it effects the signal, when used as a coupling cap, is another
matter,
an interesting test would be a Belcher test, with continuous quasi-random
noise
applied and the total IM products thus measured would be far more
indicative
of what you can expect with musical signals than a standard 2 tone IM
test.

see for a description here, page 101-103, section 3.12.3:
http://www.enigma-systems.de/manuals...promanuale.pdf


There are as many ways to measure anything in particular as the human minds
tasked to come up with novel ways to do can can ever invent. The Belcher
test is yet another example of this. All valid and relevant means for
measuring antyhing in particular produce comparable results.

"interesting" is not all by itself, a complete reason to do something,
unless time and money are in surplus.

In the end all electronic equipment adds only 3 things to an applied signal:

Nonlinear distoriton
Linear distortion
Noise

We already know that a properly-appliable capacitor exists for almost every
conceivable application in electronics, and that for almost all audio
applications, said capacitor is readily available for a reasonble price from
a number of independent sources.

[Rudy]

"Arny Krueger" wrote in message
...
:
: "Rudy" wrote in message
: b.home.nl...
:
: whether it effects the signal, when used as a coupling cap, is another
: matter,
: an interesting test would be a Belcher test, with continuous quasi-random
: noise
: applied and the total IM products thus measured would be far more
: indicative
: of what you can expect with musical signals than a standard 2 tone IM
: test.
:
: see for a description here, page 101-103, section 3.12.3:
: http://www.enigma-systems.de/manuals...promanuale.pdf
:
:
: There are as many ways to measure anything in particular as the human minds
: tasked to come up with novel ways to do can can ever invent. The Belcher
: test is yet another example of this. All valid and relevant means for
: measuring antyhing in particular produce comparable results.
:
: "interesting" is not all by itself, a complete reason to do something,
: unless time and money are in surplus.
:
: In the end all electronic equipment adds only 3 things to an applied signal:
:
: Nonlinear distoriton
: Linear distortion
: Noise
:
: We already know that a properly-appliable capacitor exists for almost every
: conceivable application in electronics, and that for almost all audio
: applications, said capacitor is readily available for a reasonble price from
: a number of independent sources.
:
as always, that isn't such a clear cut case as you'd like to make it out.

what makes audio such an interesting subject, is that it exemplifies
in many ways that the perceptive process can be seen as a multitasking
processor, having only *so much* capacity available at any time,
for instance level of attention and thus perceived detail is diminished when
we have to do several filtering and correction background processes,
for instance, to compensate the room/speaker's frequency response anomalies,
(speaker)IM distortion at higher levels/frequencies, background noise modulation,
at higher acoustical levels the mechanical distortion by the ear/canal/fluid/receptor
interface, all operating with a different "settling time" ;-),

you could say that the quest for the audio enthousiast is in
reclaiming as much as possible of that "lost processor time"
by eliminating all that compensation background processing.

small differences can make inordinately large perceived differences ;-)
Rudy

[Arny Krueger]

"Rudy" wrote in message
.home.nl...

"Arny Krueger" wrote in message
...
:
: "Rudy" wrote in message
: b.home.nl...
:
: whether it effects the signal, when used as a coupling cap, is another
: matter,
: an interesting test would be a Belcher test, with continuous
quasi-random
: noise
: applied and the total IM products thus measured would be far more
: indicative
: of what you can expect with musical signals than a standard 2 tone IM
: test.
:
: see for a description here, page 101-103, section 3.12.3:
: http://www.enigma-systems.de/manuals...promanuale.pdf
:
:
: There are as many ways to measure anything in particular as the human
minds
: tasked to come up with novel ways to do can can ever invent. The
Belcher
: test is yet another example of this. All valid and relevant means for
: measuring antyhing in particular produce comparable results.
:
: "interesting" is not all by itself, a complete reason to do something,
: unless time and money are in surplus.
:
: In the end all electronic equipment adds only 3 things to an applied
signal:
:
: Nonlinear distoriton
: Linear distortion
: Noise
:
: We already know that a properly-appliable capacitor exists for almost
every
: conceivable application in electronics, and that for almost all audio
: applications, said capacitor is readily available for a reasonble price
from
: a number of independent sources.
:
as always, that isn't such a clear cut case as you'd like to make it out.

That would be an interesting topic if you could address it rationally and
cohenrently.

snip rambling, muddled, almost random thoughts

[Rudy]

"Arny Krueger" wrote in message
...
:
: "Rudy" wrote in message
: .home.nl...
:
:: :
: as always, that isn't such a clear cut case as you'd like to make it out.
:
: That would be an interesting topic if you could address it rationally and
: cohenrently.
:
: snip rambling, muddled, almost random thoughts
:
I have to admit, my DIY transcranial magnetic stimulation device,
from an old 110deg. deflection yoke and some bits and pieces thrown
together *did* produce some odd buzzes, when i tested it on m'self,
this morning- maybe the pulse rate was a bit too high -
you think _that_ did it ?

:-)
R.

[Peter Wieck]

On Oct 26, 10:37*pm, Eeyore
wrote:

The films you mention are indeed different. That was not at dispute. What was at dispute was
whether a film of a certain chemical composition varies from manufacturer X to manufacturer Y.

Get a grip, man! Even as-stated the question forces the answer of
"NO".

Capacitors are commodities manufactured from a series of other
commodities purchased on the open market from the lowest bidder
capable of meeting a given set of specifications. It doesn't get much
simpler than that. So, supplier X, or Y or little green men from Mars
near-as-much doesn't matter as long as the particular commodity they
supply meets the need. And whatever internal differences as might
exist between these commodities will not be relevant to the
performance of the product as they are perforce entirely outside the
specified parameters.

So, using your words: If I specify a material of a "certain chemical
composition", then I will choose my supplier on the basis of price and
terms, whether X or Y or Mars - as long as the delivered product is of
a "certain chemical composition". Period.

The rest is packaging and hype.

Peter Wieck
Melrose Park, PA