+1 On Sun, Oct 27, 2024 at 4:20 PM Ralph McDiarmid <[email protected]> wrote:
> That was an interesting read. Thank you for sharing it, Ken. > > > > > > Ralph > > > > *From:* Ken Javor <[email protected]> > *Sent:* October 25, 2024 2:06 PM > *To:* [email protected] > *Subject:* Re: [PSES] current probe notes > > > > In a previous exchange, it was noted how much early work has been > forgotten. > > > > Case in point, the attachment and its references. By a couple of > gentlemen most of us on this side of the Pond knew, now sadly departed. > > > > > > > > -- > > > > Ken Javor > > Ph: (256) 650-5261 > > > > > > *From: *"doug emcesd.com" <[email protected]> > *Reply-To: *"doug emcesd.com" <[email protected]> > *Date: *Friday, October 25, 2024 at 1:12 PM > *To: *<[email protected]> > *Subject: *[PSES] current probe notes > > > > Hi All, > > > > I want to discuss current probes a bit. They are among the most useful > tools available to engineers. > > > > Current probes are very useful in EMC, ESD, and other troubleshooting and > are required in some standards like conducted immunity testing. But current > probes cannot be adequately characterized by the well published equations. > For one, E field response is an undesirable characteristic that makes many > current probes useless when used to measure ESD currents and some other > applications. > > > > I have used a Fischer Custom Communications F-65 current probe for many > years. Not only does it have a negligible E-field response, and therefore > useful for ESD measurements and troubleshooting, but also has a flat > frequency response over three orders of magnitude from about 1 MHz to 1 > GHz. Designing anything that is not a 50 Ohm matched structure and has a > flat frequency response for three orders of magnitude in a range where > parasitics are important to account for is very difficult and requires a > lot of experience. Current probe equations alone will not lead to a > satisfactory design. This material is generally not treated adequately in > my opinion in the engineering community except by me. > > > > That brings me to low-cost current probes I have seen on the market. One > I checked out a few years ago had an E-field response that was equal to 50% > of the H-field response, making more or less useless for that application, > but users of that probe would normally have no idea their data was more or > less useless. > > > > If one buys an inexpensive current probe (less than $1000) it may very > work fine, but you cannot assume that it works unless the manufacturer > publishes its E-field response and how that response was measured, or you > measure the response by one of several methods I have published and teach. > The problem with verifying the probe oneself is that an engineering > employee cost to a company is on the order of $2,000 per worked day these > days, especially in areas of lots of technology like Silicon Valley, so > buying inexpensive equipment may not be the savings one thinks! > > > > Doug (current probe) Smith > > [image: Image removed by sender.] > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > [email protected] > > All emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/[email protected]/ > <https://www.mail-archive.com/[email protected]/%20> > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: [email protected] > Rick Linford at: [email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > [email protected] > > All emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/[email protected]/ > <https://www.mail-archive.com/[email protected]/%20> > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: [email protected] > Rick Linford at: [email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > [email protected] > All emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/[email protected]/ > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: [email protected] > Rick Linford at: [email protected] > > For policy questions, send mail to: > Jim Bacher at: [email protected] > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
