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.

On Wed, 17 Mar 2004 15:45:34 -0000, "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?

Silly boy......

Sorry. I'll try not to ask such *stupid* questions again.
--

The BBC: Licensed at public expense to spread lies.

On Wed, 17 Mar 2004 15:45:34 -0000, "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?

Silly boy......

Sorry. I'll try not to ask such *stupid* questions again.
--

The BBC: Licensed at public expense to spread lies.

Behold, Paul Burridge signalled from keyed 4-1000A filament:

On Wed, 17 Mar 2004 12:30:56 GMT, Gregg wrote:

Hi Paul!

There are non-inductively wound ones specifically for the purpose. The
mfr. specs should show an ESR curve - the non-inductive ones are pretty
flat to their SRF.

I notice some of them come with one end tinted red (or sometimes black).
Does this indicate the non inductively-wound type?


Nope. That just indicates the "outside" foil - commonly goes to ground.

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca

Behold, Paul Burridge signalled from keyed 4-1000A filament:

On Wed, 17 Mar 2004 12:30:56 GMT, Gregg wrote:

Hi Paul!

There are non-inductively wound ones specifically for the purpose. The
mfr. specs should show an ESR curve - the non-inductive ones are pretty
flat to their SRF.

I notice some of them come with one end tinted red (or sometimes black).
Does this indicate the non inductively-wound type?


Nope. That just indicates the "outside" foil - commonly goes to ground.

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca

On Wed, 17 Mar 2004 23:01:13 -0000, the renowned "Emoneg"
wrote:


Gosh! Zero tempco decoupling for the digital folks.
DNA

The Z5U parts pretty much magically disappear if you get them cold..
but X7R is good enuf.

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 Wed, 17 Mar 2004 23:01:13 -0000, the renowned "Emoneg"
wrote:


Gosh! Zero tempco decoupling for the digital folks.
DNA

The Z5U parts pretty much magically disappear if you get them cold..
but X7R is good enuf.

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 Wed, 17 Mar 2004 12:03:06 +0000, Paul Burridge
wrote:

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.

They're great for LC filters. If you choose your ferrite right, you
can have a pretty stable filter over temperature. Problem is, not many
people make these any more. For production, avoid them due to
availability. If you're worried about inductance, that probably means
that you're in the MHz region which means you can use NPO (COG)
ceramic. Easier to get.

Mark

On Wed, 17 Mar 2004 12:03:06 +0000, Paul Burridge
wrote:

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.

They're great for LC filters. If you choose your ferrite right, you
can have a pretty stable filter over temperature. Problem is, not many
people make these any more. For production, avoid them due to
availability. If you're worried about inductance, that probably means
that you're in the MHz region which means you can use NPO (COG)
ceramic. Easier to get.

Mark

Behold, qrk signalled from keyed 4-1000A filament:

On Wed, 17 Mar 2004 12:03:06 +0000, Paul Burridge
wrote:

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.

They're great for LC filters. If you choose your ferrite right, you can
have a pretty stable filter over temperature.

Air-core my good man, air-core ;-)

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca