On Thu, 05 Dec 2013 14:42:02 -0600, John S
wrote:

On 12/5/2013 1:49 PM, John S wrote:

Well I did it using an old dirty trick:
adding one fake data point at the end to bend the curve.

http://img560.imageshack.us/img560/1845/yi2.gif

You must then not use the values
which are above the last valid data point.

You may program this formula into an Arduino .-)

w.

Yes, the trend line is very close. But, please perform a calculation on
the 498R value using the equation and let me know if it agrees. If yours
does, then something is wrong here.

Thanks,
John


Helmut -

Please see this. I think Excel is screwed up.

https://imageshack.com/i/mrg919p


Yes, you are right.
Although EXCEL calculated the curve correctly in its own diagram,
it outputs false (rounded) parameters for the curve fitting polynom.
Compare with the Graphmatica plot, they are ident.
Have to find out tomorrow how to get the polynom factors without
rounding errors, if possible.
http://img834.imageshack.us/img834/8177/altv.gif

w.