I found this one during my research but have not had time to do any = testing to validate its correctness, so this is given as found: ----------------------------------------- I-cont =3D Continuous Current (Need to know max current rating of via) F=3D Fraction of "ON" time Where F =3D Fraction of "ON" time. =3D ( ON TIME/(ON TIME+OFF TIME)) I-pulsed =3D I-cont/sqrt of F ------------------------------------------ Example: I-cont =3D .47 amps An "ON" time of 1 millisecond and "OFF" time of 9 milliseconds. F=3D 1/1+9=3D0.1 I-pulsed=3D 0.47amps/sqrt0.1 =3D 1.49 amps can be pulsed through at = 1msec. --------------------------------------------- If you or anyone else on the SI-list test out this formula let me know = how it compares to measurements. Hariharan, I'd also be interested if anyone else sends you something regarding this subject- please forward if it is not replied to SI-list = also. Regards, Rich -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of hariharan Sent: Friday, May 09, 2003 2:15 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] current carrying capacity of Via with time Hi, I'd like to know how to calculate whether a via can withstanda 25 amps = of current for 2-3 sec? Is there any formula for this? regards Hariharan ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list 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