[sdiy] Tempco 2k +3350ppm Group buy

[Heitor Alves]

I'm sorry to "put my nose" on the talk... have any of you guys tryed
http://www.micro-ohm.com/temperature/temprecflm.html this company? I dont
know if they make thoses values, but the +3500 they make them..

i've asked once for samples of 1k and 2k +3500 but i had no chance to test
them yet... they are very nice persons (at least the one i've talked).

hope it helps!




On 20/05/06, HA.Synth at t-online.de <HA.Synth at t-online.de> wrote:
>
> Thanks Ryan,
>
> looks like I should go for +3500. But I have one questons. If i look at
> the
> tracking chart of PT146-35 it says 3440ppm at 25 and 3500ppm at 100degC.
> In your paper you wrote +3369 at 25C and +3430 at 100C.
> If I look at RES/TEMP CURVE at their site I can read +3369 at 25C and
> +3420 at
> 100C.
> What am I missing here? Is the tracking chart wrong?
>
> Harald
>
> > hi,
> >
> > for precisionresistor.com tempcos, I believe that +3500 is the correct
> > part to buy. They specify that these are actually more like +3369 at
> > room temperature. thats pretty close to to the +3355 that is needed. The
> > problem is how they measure tcr and they comment on using the +3500ppm
> > instead of the lower +3350ppm at the website. the tcr isn't linear and
> > there is some tolerance on the parts anyway. It would be better to have
> > a tcr that is to high than too low since correcting the error is easier
> > that way. I wrote some document about using the precisionresistor PT146
> > here:
> > http://www.sdiy.org/destrukto/notes/tempco_calculations_pt1.pdf
> >
> > note: most credit goes to Ian for this since it was his analysis and
> > answers to my questions that helped me write it.
> >
> > btw. if anyone sees a problem, let me know so I can correct it.
> >
> > Ryan Williamsf
>
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