A current probe measures the net current on the conductor within its opening. The impedance of the circuits attached to that conductor may affect how much current flows through the conductor, but not the measurement thereof.
Ken Javor Phone: (256) 650-5261 From: Amund Westin <am...@westin-emission.no> Reply-To: Amund Westin <am...@westin-emission.no> Date: Wed, 13 Jan 2016 18:48:23 +0100 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] Current probe for CM currents Planning to do some EMI troubleshooting with a «homemade» current probe. Probing a lot of cables inside a rack and try to find the source. Will make a current probe by a ferrite core (two halves, a few turns wire and coax plug) as many EMI experts have posted on the web and on this forum. Then find the Zt[dBohm], so make a measurement on a cable and verify the readings on the spectrum. But when clamping on the current probe, which is a ferrite, does that change the cable impedance and therefore actually changes the real current flow, so my reading will not be true? ... or am I missing some fundamental theory here? ... #Amund - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
