no, or not always, or not anymore ;) -first of all, the 1% and 5% being tolerances , are usually specified either at standard temperature (like 25deg C) , or across temperature range. IF the specs are at 25deg C , they don't imply any kind of temperature performance . There will be no relationship whatsoever between a resistor being 1% across temperature and being sold as 1% tolerance. Life is not that easy. There might be different temperature coefficients involved depending on the resistors' technology but that's another story ,they might even be non-linear with temperature . -long ago ,when resistor materials manufacturing costs were the predominant part in the resistor retail price (or so the legend said) , some vendors used to sort their resistors . That way, they were making only 5% parts. They were picking the parts which were within +/-2% and +/-1% from the 5% batch and marked them as 2% and 1% . I recall someone having "fun" one day , plotting a whole resistors box distribution only to figure out if they were selected as 1% or unselected. The idea was that if they were unselected, we could've selected them for 0.1%, otherwise the middle of the curve was gone and sold as 0.1% . Now, time is a lot more important than materials for resistors , processes are a lot more under control, so I doubt any resistor manufacturer is selecting 1% out of the 5% bin. They might do it for specialty parts , low volume and/or low yield high precision parts but not the 5%.
- as a sidenote, the cherry picking procedure makes Monte-Carlo analysis somewhat useless, unless the problem was trivial . That is because the cherry picked parts don't obey any random distribution curve so the combinations Monte-Carlo is calculating in that case don't really exist. Best Regards, Matt Tudor , MSEE http://www.gigahertzelectronics.com ----- Original Message ----- From: "Andy Gulliver" <[EMAIL PROTECTED]> To: "Protel EDA Forum" <[EMAIL PROTECTED]> Sent: Tuesday, July 02, 2002 6:44 AM Subject: Re: [PEDA] AW: SPICE sim question > Also, in practice you'll be very lucky to find a resistor sold as 5% that is > within 1% across temperature etc. - they're the ones that are being sold as > 1% parts! > > Regards, > > Andy Gulliver ************************************************************************ * Tracking #: 1196B5D30963FF4A88A728F6367207E6F00B1513 * ************************************************************************ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
