mcgradys wrote:
Hi all,

Newbie to this forum, but need some excel help. I have collected a
bunch of data from an object as it heats up. The curve is very similar
to a capacitor charging current curve. In my case, manually trying to
approximate this curve, I come up with a formula of y=
(rise)*(1-exp(-time))+ambient. Is there a way in excel to fit a curve
like this or do I need an aftermarket solution? I need something that
will use the data points and perform calculations to determine the
curve.

Thanks,

Sean




Have you tried to use the Solver? Set up a table with a column of empirical
data, a column of calculated data using your equation, and a column with the
square of the error between the two with a sum at the bottom. The calculated
data needs to be calculated using spreadsheet cells to store each of the
parameters you're trying to fit.

Then ask Tools/Solver to minimize the sum of the column of squared errors by
varying the paramater value cells.

I suspect Solver will work pretty well with this kind of problem.

Good luck...

Bill