I'm playing with some transistor test data and having trouble understanding what is probably a very basic principle.
Below are my two graphs, plotted linearly and then with a logarithmic scale on the y axis. (Absolute vals for y taken.)
I understand that my linear values approach zero and log10(0) = -Inf, so the huge drop off in values as x -> 0 makes sense. But I haven't quite grokked converting back and forth yet.
I'm attempting to do some curve fitting to get the gradient in a pretty good linear region which can be used to calculate junction temperature etc. I'm plotting using semilogy, sighting a range to use as my linear region, then feeding that forward to perform the fitting. As the data stays in a protected structure, I want that range in terms of the non-log values (is it obvious my field is programming not maths..?).
How do I convert back? I can look at the graph and see that it is linear enough for my purposes between 10^-6 and 10^-1 but then how does that relate to my actual data?
log10(a) = b -> 10^b = a, yep, but using the range above:
10^(10^-6) = 1.0000023..
10^(10^-1) = 1.2589254..
And then I remembered I had taken the abs value so..
-10^(10^-6) = -0.9999..
-10^(10^-1) = -1.2589..
All of which are out of range of the original data.
I want to be able to say minY = someOperation(10^-6), maxY = someOperation(10^-2)
Thank you for reading, Marshall