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.