Hi Mick! Aside from the differences (plated vs anealed, pure vs alloyed and layered) others have pointed out, is it possible you had a sign error in your calculations? resistivities for copper are in the mid e+7s not e-7s as you have below. Aubrey Sparkman Signal Integrity Aubrey_Sparkman@xxxxxxxx (512) 723-3592 > -----Original Message----- > From: Zhou, Xingling (Xingling) [mailto:xlzhou@xxxxxxxxx] > Sent: Monday, August 13, 2001 9:07 AM > To: Si-List (E-mail) > Subject: [SI-LIST] Resistance > > > > Hi, > > When you calculate the DC resistance of wires and traces, > which resistivity > values should be used or more practical ? Most books give > 1/5.8e-7 = 1.724e-8 for pure cooper. However, Dr. Johnson's book gives > 6.787e-7 (p.411) and he explained his reasons. On p.409, he > mentioned that " > the authors have used MathCad to evaluate each of the > following formulas in > well-known test cases...". Obviously, the > two values are quit different, three times ! So, please provide your > suggestion ? > > Thanks. > > Mick > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu