Tektronix Keithley 2651A Reference Manual page 143

Model 2651A High Power System SourceMeter® Instrument Reference Manual
The formula for a logarithmic sweep is:
i
v = A + kb
i
Where:
v = The source value at source point i
i
= The index of points in the sweep (ranges from 0 to N − 1), where N is
i
the number of points in the sweep
k = The initial source value as an offset from the asymptote
b = The step size ratio
A = The asymptote value
The asymptote is used to change the inflection of the sweep curve and allow it to sweep through zero.
The following figures depict the effect of the asymptote on the inflection of the sweep curve.
2651A-901-01 Rev. C October 2021
Figure 39: Increasing logarithmic sweep
Section 3: Functions and features
3-25