On Wed, 17 Mar 2004 15:45:34 -0000, the renowned "Emoneg"
wrote:


"Paul Burridge" wrote in message
.. .
| Hi,
|
| They look worryingly inductive on visual inspection (there are metal
| foils rolled up in thar by the look of it.) And yet the CPC catalogue
| says that their properties make them ideal for use in filters. Has
| anyone any remarks (favourable or otherwise) to make about the use of
| this type of cap in filter apps?
|
| p.
| --
|
| The BBC: Licensed at public expense to spread lies.

Silly boy...... Go and find out about construction methods. The
metallisation is offset so the end terminations parallel the internal
layers.

DNA

Yup. Take two sheets of letter-size (okay, A4) paper and lay one on
top of the other but the top one to the right by 1/2". These are like
the plates of your capacitor. Now roll them up from the bottom to the
top into a tight roll. Imagine you connect to all the right end (in
parallel) by dipping it in some conductive goop, and call that lead A.
Do the same to the left, and call it lead B. The coiled construction
adds no inductance.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Yeah, they're rolled up, but the contact is made across the ends,
generally, not just at one location in the roll. (That's why you
should build that vector network analyzer...) But I'd avoid them:
they can't take the heat. C0G ceramics and polyprops are both good.
C0G ceramics are available up to 10nF or so even in SMT; polyprops
down to 1nF at least and up to many uF.

Cheers,
Tom

Paul Burridge wrote in message . ..
Hi,

They look worryingly inductive on visual inspection (there are metal
foils rolled up in thar by the look of it.) And yet the CPC catalogue
says that their properties make them ideal for use in filters. Has
anyone any remarks (favourable or otherwise) to make about the use of
this type of cap in filter apps?

p.

Yeah, they're rolled up, but the contact is made across the ends,
generally, not just at one location in the roll. (That's why you
should build that vector network analyzer...) But I'd avoid them:
they can't take the heat. C0G ceramics and polyprops are both good.
C0G ceramics are available up to 10nF or so even in SMT; polyprops
down to 1nF at least and up to many uF.

Cheers,
Tom

Paul Burridge wrote in message . ..
Hi,

They look worryingly inductive on visual inspection (there are metal
foils rolled up in thar by the look of it.) And yet the CPC catalogue
says that their properties make them ideal for use in filters. Has
anyone any remarks (favourable or otherwise) to make about the use of
this type of cap in filter apps?

p.

On 17 Mar 2004 10:12:04 -0800, the renowned (Tom Bruhns)
wrote:

Yeah, they're rolled up, but the contact is made across the ends,
generally, not just at one location in the roll. (That's why you
should build that vector network analyzer...) But I'd avoid them:
they can't take the heat. C0G ceramics and polyprops are both good.
C0G ceramics are available up to 10nF or so even in SMT; polyprops
down to 1nF at least and up to many uF.

Would you believe 100nF/25V C0G in 1206? Not insanely expensive
either.

http://www.murata.com/catalog/c02/es0011.pdf1206? (page 5)

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On 17 Mar 2004 10:12:04 -0800, the renowned (Tom Bruhns)
wrote:

Yeah, they're rolled up, but the contact is made across the ends,
generally, not just at one location in the roll. (That's why you
should build that vector network analyzer...) But I'd avoid them:
they can't take the heat. C0G ceramics and polyprops are both good.
C0G ceramics are available up to 10nF or so even in SMT; polyprops
down to 1nF at least and up to many uF.

Would you believe 100nF/25V C0G in 1206? Not insanely expensive
either.

http://www.murata.com/catalog/c02/es0011.pdf1206? (page 5)

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

In article , Paul Burridge
writes:

They look worryingly inductive on visual inspection (there are metal
foils rolled up in thar by the look of it.) And yet the CPC catalogue
says that their properties make them ideal for use in filters. Has
anyone any remarks (favourable or otherwise) to make about the use of
this type of cap in filter apps?

BIG difference between two types of rolled-foil style or "tubular"
capacitors even at MF. For MF or even LF, use the low-inductance
"extended foil" type; manufacturers will indicate that difference on
datasheets, catalog listings.

Extended-foil construction offsets the layering so that one foil
overlaps the insulating film or paper at one end, the other foil
overlapping the other end. When axial leads are attached, the
foil overlaps is crimped down on the lead so that nearly all turns
of the foil at one end contact the lead. Minimum inductance.

Conventional old style of construction had the two foils neatly
aligned with no foil protruding from the wider insulating layers.
Axial leads were then clamped at only one end of the foil wrap
end (usually the finish end) and the result had a fair amount of
residual inductance in the remainder of the foil wrapping.

A few makers introduced deliberately series-resonant bypass
tubulars many years ago, intended for the ubiquitous 455 KHz
IF amplifier stage bypassing. Broad series resonance but it
worked (sort of). Rather a rare tubular now. Curiosity.

Len Anderson
retired (from regular hours) electronic engineer person

In article , Paul Burridge
writes:

They look worryingly inductive on visual inspection (there are metal
foils rolled up in thar by the look of it.) And yet the CPC catalogue
says that their properties make them ideal for use in filters. Has
anyone any remarks (favourable or otherwise) to make about the use of
this type of cap in filter apps?

BIG difference between two types of rolled-foil style or "tubular"
capacitors even at MF. For MF or even LF, use the low-inductance
"extended foil" type; manufacturers will indicate that difference on
datasheets, catalog listings.

Extended-foil construction offsets the layering so that one foil
overlaps the insulating film or paper at one end, the other foil
overlapping the other end. When axial leads are attached, the
foil overlaps is crimped down on the lead so that nearly all turns
of the foil at one end contact the lead. Minimum inductance.

Conventional old style of construction had the two foils neatly
aligned with no foil protruding from the wider insulating layers.
Axial leads were then clamped at only one end of the foil wrap
end (usually the finish end) and the result had a fair amount of
residual inductance in the remainder of the foil wrapping.

A few makers introduced deliberately series-resonant bypass
tubulars many years ago, intended for the ubiquitous 455 KHz
IF amplifier stage bypassing. Broad series resonance but it
worked (sort of). Rather a rare tubular now. Curiosity.

Len Anderson
retired (from regular hours) electronic engineer person

"Spehro Pefhany" wrote in message
...
|
| Would you believe 100nF/25V C0G in 1206? Not insanely expensive
| either.
|
| http://www.murata.com/catalog/c02/es0011.pdf1206? (page 5)
|
| Best regards,
| Spehro Pefhany
| --
| "it's the network..." "The Journey is the
reward"
| Info for manufacturers:
http://www.trexon.com
| Embedded software/hardware/analog Info for designers:
http://www.speff.com

Gosh! Zero tempco decoupling for the digital folks.

DNA

"Spehro Pefhany" wrote in message
...
|
| Would you believe 100nF/25V C0G in 1206? Not insanely expensive
| either.
|
| http://www.murata.com/catalog/c02/es0011.pdf1206? (page 5)
|
| Best regards,
| Spehro Pefhany
| --
| "it's the network..." "The Journey is the
reward"
| Info for manufacturers:
http://www.trexon.com
| Embedded software/hardware/analog Info for designers:
http://www.speff.com

Gosh! Zero tempco decoupling for the digital folks.

DNA

On Wed, 17 Mar 2004 18:21:12 GMT, Spehro Pefhany
wrote:

On 17 Mar 2004 10:12:04 -0800, the renowned (Tom Bruhns)
wrote:

Yeah, they're rolled up, but the contact is made across the ends,
generally, not just at one location in the roll. (That's why you
should build that vector network analyzer...) But I'd avoid them:
they can't take the heat. C0G ceramics and polyprops are both good.
C0G ceramics are available up to 10nF or so even in SMT; polyprops
down to 1nF at least and up to many uF.

Would you believe 100nF/25V C0G in 1206? Not insanely expensive
either.

It's almost as if they can defy the laws of physics these days....
Next thing you know: 100A FETs in the same package. :-|
--

The BBC: Licensed at public expense to spread lies.