Muriel: That circuit is OK. All source impedances upstream of the LISN are undefined. The source power voltage applied to the lISN can be anything as long as it doesn't exceed the LISN max voltage rating. The LISN, by definition, produces the standardized source impedance for the EUT.
Yes, the transformer will be a bit "lossy" at RF frequencies. But that's not only OK, it's good. You want to eliminate as much noise from the power source as possible. Heck, put the EUT in a shielded room, use monstrous powerline filters where the power penetrates the room, and test in luxurious quiet! :-) Don't forget to be careful of power lead placement and EUT grounding from test to test. Regards, Ed ------------------------ From: Muriel Bittencourt de Liz <[email protected]> Subject: Doubt on LISN utilization Date: Wed, 21 Oct 1998 15:00:01 -0200 To: Lista de EMC da IEEE <[email protected]> > Hello, > > I'm doing some tests of conducted emission using a LISN. My commercial > voltage level is 220 V, 60Hz. But the product i'm testing is 110 V. So, > i'm using a transformer before the LISN this way: > > Mains => Transformer(220/110) => LISN => EUT ( Equipment Under Test ) > > My questions are: > > # am i doing right? > # is it possible to use a transformer? > # isn't the transformer acting like a "unintentional" filter? > > Any help will be welcome. > > Sincerely > > Muriel > > -- > > ================================================== > > Muriel Bittencourt de Liz > INEP - Instituto de Eletronica de Potencia > Universidade Federal de Santa Catarina > Caixa Postal - 5119 > 88.040-970 - Florianopolis - SC - BRASIL > Phone: +55.48.331.9204 - Fax: +55.48.234.5422 > e-mail: [email protected] > Homepage: http://www.inep.ufsc.br > > ================================================== -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 10/21/1998 Time: 11:54:27 -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
