SV: Re: SV: Re: SV: Re: [sdiy] Compensating PTC and NTC resistors

[karl dalen]

--- René Schmitz <uzs159 at uni-bonn.de> skrev:

> Hi Neil and all,
> 
> Neil Johnson schrieb:
> > From: karl dalen <dalenkarl at yahoo.se>
> > 
> >> So are Elbys calculations right or wrong?!
> >> http://www.elby-designs.com/datasheets/tempco.pdf
> > 
> > (minor correction)
> > 
> > As Ian said, the *equation* is correct, the *numbers* are a little off.
> 
> Correct, but still only of theoretical interest, because you don't 
> really know the *actual* tempco of the series resistor. Could be +50 or 
> -50ppm... If you stick in 0 for TC2 it degrades to the form I have been 
> using. If you stick in the borders, you can use it to assess how large 
> the errors might be.

Please Rene could you explain the idea of using 0 TC of a MFR as means
to compensate down the 3900ppm of the PTC? I *gladly* admit (once again)
i have no clue  how that works? What is it in TC2 that makes PTC TC1 to
degrade?

KD 

 
> 
> Cheers,
>   René
> 
> 



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