Keithley 2651A Reference Manual page 132

Model 2651A High Power System SourceMeter® Instrument Reference Manual
In this example:
A = 0, V
start
Using the formula above, k = 1
Step size (b) for the sweep in the above figure is calculated as follows:
Therefore, b = 10
The five log steps for this sweep are listed in the Logarithmic sweep points table below.
Logarithmic sweep points
Source point (N)
1
2
3
4
5
When this sweep starts, the output will go to the start level (1 V) and sweep through the symmetrical
log points.
To configure a logarithmic staircase sweep, use the smuX.trigger.source.logY()function. This
function configures the source values the source-measure unit (SMU) will output when performing a
logarithmic sweep. After configuring the sweep, you must also enable the source action by setting the
following attribute:
smua.trigger.source.action
Example:
-- Sweep from 1 to 10 V in 10 steps with an asymptote of 0 V.
smua.trigger.source.logv(1, 10, 11, 0)
-- Enable the source action.
smua.trigger.source.action = smua.ENABLE
For more information, see smuX.trigger.source.logY().
2651A-901-01 Rev. A / March 2011
= 1, V = 10, N = 5
end
log10(stop-0) log10(start-0)
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Log Step Size = ---------------------------------------------------------------------------- -
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⎜
⎜ log10(10) log10(1)
= ---------------------------------------------------- -
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⎜
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⎝
(log step size)
= 1.7783
Source level (V)
1
1.7783
3.1623
5.6234
10
–
Points 1
–
–
5 1
–
( )
1 0
–
= ---------------- -
4
= 0.25
Step number (i)
0
1
2
3
4
Section 3: Functions and features
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