Agree with ED, the las time I used and electronic load it was terrible noisey in-and-of-itself. Too noisey for emissions tests. As lab equipment – at the time – it didn’t hgave any FCC emissions testing – and so I doubt it addressed this area at all. Maybe better these days but I would be skeptical until I tested a sample.
Gary _____ From: [email protected] [mailto:[email protected]] On Behalf Of Price, Ed Sent: Thursday, May 18, 2006 8:36 AM To: [email protected] Subject: RE: Conducted emission measurements > -----Original Message----- > From: David Gelfand [mailto:[email protected]] > Sent: Thursday, May 18, 2006 8:09 AM > To: [email protected] > Subject: Conducted emission measurements > > We measured conducted emissions of a switched mode ac-dc > power supply and found that emissions are much higher when > using an electronic load compared to a resistive load. Can > somebody explain why this is? > > Thanks, > > David. > > David Gelfand, P.E. > Product Integrity Engineer > Mitec Telecom Inc > 9000 Trans-Canada Highway > Montreal QC H9R 5Z8 > Canada > 514 694 9000 x2262 Dave: I would imagine that the electronic load is itself a noise source. You are likely seeing the noise of the load, filtered and isolated by the power supply. Further, the power supply might not like the noise of the electronic load, and respond with even more power supply noise. Also, the electronic load may be providing a common mode path for power supply output noise. I generally avoid electronic loads, but it could be argued that a digital load looks a lot more realistic than a stack of non-inductive resistors. You should know what happens when your power supply is feeding real electronics as well as a passive load. Regards, Ed Price [email protected] WB6WSN NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Is Our Specialty - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
