Keithley 2500

Models 2500 and 2502 User’s Manual Sweep Operation 9-3
Logarithmic staircase sweep
This sweep is similar to the linear staircase sweep. The steps, however, are done on a loga-
rithmic scale as shown in the example sweep in Figure 9-2. This is a 5-point log sweep
from 1 to 10V. As with the staircase sweep, the delay period is the same for all steps.
Figure 9-2
Logarithmic staircase sweep (example 5-point sweep from 1 to 10 volts)
The programmable parameters for a log sweep include the start and stop levels and the
number of measurement points for the sweep. The specified start, stop, and point parame-
ters determine the logarithmic step size for the sweep. Step size for the sweep in
Figure 9-2 is calculated as follows:
Start
Bias
Stop
(10)
Measure
#1
Measure
#2
Measure
#3
Measure
#5
X = Measurement Point
X
X
X
X
X
Measure
#4
Log Points = 5
1
10
5.6234
3.1623
1.7783
Volts
Log
Scale
Delay
Delay
Delay
Delay
Delay
Log Step Size
log10(stop) log10(start)–
Points 1–
-------------------------------------------------------------=
log10(10) log10(1)–
51–
--------------------------------------------------=
10–()
4
----------------=
0.25=
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