ELE 343 Electronics II
This tutorial demonstrates the use of EXCEL to Evaluating Formulas The excel sheet data shown in Figure 1 represents transistor currents. To calculate the transistor beta (Ic/Ib) at different transistor currents;
More complex formulas can be evaluated. 
Figure 1 
Plotting Data Problem: Plot the log of Ib and Ic vs Vbe Solution:

Figure 2

 Figure 3

be sure zero or negative values are not included.  Select a minimum greater than zero and check "logarithmic scale". 
Fitting Data to a Formula
A formula representation of the collector current data can be obtained.
Ic = IS e^{Vbe/(NF Vt)}where IS and NF are SPICE model parameters and Vt = KT/q = 0.0259V at T=300 degrees Kelvin.
Matching the EXCEL and SPICE formulas for Ic allows two important SPICE model parameters to be determined.
IS = 2E15
NF = 0.95