Tektronix Keithley 2651A Reference Manual page 144

Section 3: Functions and features
Solving for k and b provides the following formulas:
Where:
V
= The source value at the end point
end
V = The source value at the start point
start
N
= The number of points in the sweep
A
= The asymptote value
The number of points in a sweep is one greater than the number of steps in the sweep.
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Model 2651A High Power System SourceMeter® Instrument Reference Manual
Figure 40: Decreasing logarithmic sweep
2651A-901-01 Rev. C October 2021