Keithley 6430

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.
The programmable parameters for a log sweep include the start and stop levels and the num-
ber of measurement points for the sweep. The specified start, stop, and point parameters deter-
mine the logarithmic step size for the sweep. Step size for the sweep in Figure 9-2 is calculated
as follows:
Delay
Delay
Delay
Delay
Start
Bias
Stop
(10)
Measure
#1
Measure
#2
Measure
#3
Measure
#5
X = Measurement Point
X
X
X
X
Delay
X
Measure
#4
Log Points = 5
1
10
5.6234
3.1623
1.7783
Volts
Log
Scale
Fi
gure
9
-
2
Logarithmic stair-
case sweep (example
5
-point sweep from
1 to 10 volts)
Log Step Size
log10(stop) log10(start)–
Points 1–
-------------------------------------------------------------=
log10(10) log10(1)–
5 1–
--------------------------------------------------=
1 0–( )
4
----------------=
0.25=