I read in !emc-pstc that Barker, Neil <[email protected]> wrote (in <[email protected]>) about 'BNC connectors with integrated caps to ground' on Thu, 20 Mar 2003:
>The caps are in the panel mount connector. >These are isolated BNC connectors, where the body is plastic. >The caps are embodied within the plastic body and are chip >capacitors that lie between the outer 'tube' of the BNC and >a spring clip that stakes into the ground on your PCB and >also wraps around to be sandwiched between the panel and the >body of the connector. The theory is that the loop area is very >small, <1 sq. cm.. >A few years ago I could have pointed you at several suppliers, >but I have just looked at a few catalogues and could not find any. >Perhaps this reflects my own experience that they do not perform >as well as the theory would have you believe. You could look in >more detail at manufacturers such as MA-COM, Telegartner, and >Radiall. >I would add that I have had a lot more success with totally >shielded pcb-mount BNC connectors. The integrity of the ground >structure involving panel, pcb ground plane, and connector body >seems to be particularly effective. In a somewhat similar application, I have found that *discoidal* capacitors (such as AVX make) are much better at filtering than SMD chips, and seem to behave as resistors rather than inductors at extreme frequencies, giving attenuation more or less independent of frequency instead of inversely proportional. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
