Keithley 2182, User Manual, Page: 332 / 339

I-16 Delta, Pulse Delta, and Differential Conductance
Differential Conductance calculations
dV calculations
While the dV calculations for the first six dV readings are shown in
Figure I-7
, the follow-
ing formula can be used to calculate any dV reading in the test:
Where: X, Y, and Z are the three A/D measurements for a dV reading.
n = Reading Number – 1
Example – Calculate the 21st dV reading:
X, Y, and Z are the three A/D measurements for the 21st dV reading.
n = Reading Number – 1
= 21 – 1
= 20
Therefore;
The (-1)
n
term in the dV calculation is used for polarity reversal of every other calculated
dV reading. This makes all calculated dV readings in the test the same polarity.
Simplified dV calculation
The above dV calculation can be simplified as follows:
dV
X Y
– ( )
2
-----------------
Z Y
– ( )
2
----------------- +
2
------------------------------------------
1 – ( )
n
• =
dV
X Y – ( )
2
-----------------
Z Y – ( )
2
----------------- +
2
------------------------------------------ 1 – ( )
20
• =
X Y
– ( )
2
-----------------
Z Y
– ( )
2
----------------- +
2
------------------------------------------ =
dV
X Y – Z Y – +
2
--------------------------------
2
--------------------------------
1 – ( )
n
• =
dV
X 2 Y – Z +
4
--------------------------
1 – ( )
n
• =