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I have a resistor divider, I'm interested calculating the drift of the divider over temperature and if possible minimizing it. I was wondering if both resistors in the divider have the same value picked from the same reel, can I assume that the temperature coefficient of both resistors cancel each one out? if not how much variance can I expect between the temp coeffs? I know this relies on resistor types and ...., I just want to know if anyone has tested this and knows a ballpark for typical resistor values laying around with temp coeffs around 200ppm

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    \$\begingroup\$ It would be reasonable to expect matching to better than 1/3 the maximum, possibly considerably better, but you can't know what happened, possibly the machinery was remodelled and painted lurid green between resistors in the reel or two different machines were used and the resistors mixed in a vibratory feeder. Not likely, but possible. \$\endgroup\$ – Spehro Pefhany Jan 29 '15 at 12:49
  • \$\begingroup\$ Or sun was shining for the one, and somone opened the production hall in freezing cold for the other. \$\endgroup\$ – PlasmaHH Jan 29 '15 at 13:29
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    \$\begingroup\$ I'm not sure what your budget is, but I've used the 0.1% resistors from Susumu, (RG series) Temp coef. is 25 ppm/C, ~$0.10 each in hundreds. (less if you buy the whole reel.) \$\endgroup\$ – George Herold Jan 29 '15 at 14:38
  • \$\begingroup\$ the question is not related to the budget, the same question applies to 25ppm resistors, I'm just wondering if it's practical to improve temp coef. this way and how much improvement could be expected \$\endgroup\$ – Ali80 Jan 29 '15 at 15:50
  • \$\begingroup\$ I simply do not know the answer BUT, tempco is usually a material property. If the two resistors are made of the same material, I would expect them to have similar tempcos. Suggest you contact vendor. \$\endgroup\$ – mkeith Jan 30 '15 at 17:11
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I took some quick measurements, I made a divider using resistors with 50ppm temp coef. and the divider temp coef. The worse error for a divider with equal resistors would be TC/2 which would be 25ppm, the value I measured was near 10ppm so approximately 2.5 times improvement in temp coef. for my case. I only took one measurement and I know that's not statistically right but that's enough answer for me.

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