Keithley 4200A-SCS Reference Manual page 296

Model 4200A-SCS Parameter Analyzer Reference Manual Section 6: Clarius
Voltage Log Sweep operation mode - SMU
The Voltage Log Sweep operation mode allows you to sweep over a large range and plot the
measurements on a logarithmic scale.
A linear sweep is typically unsatisfactory for such applications, because the first increment can miss
several of the lower decades. For example, the first ~0.1 V step of a 101-point linear sweep from
0.001 V to 10 V misses the two decades between 0.001 V and 0.1 V.
By contrast, a log sweep varies the step size logarithmically over the specified range, so that all
decades are characterized uniformly.
An example of a log sweep is shown in the following figure.
Figure 227: Example logarithmic sweep
4200A-901-01 Rev. C / February 2017 6-27