Keithley 2182, User Manual, Page: 326 / 339

I-10 Delta, Pulse Delta, and Differential Conductance
Pulse Delta calculation example
3-point measurement technique – Assume you want to measure the voltage across a low
power 1
Ω
DUT. The Pulse Delta process will reduce DUT heating and eliminate the
effects of thermal EMFs.
Assume the Model 6221 is configured to 10mA and 0mA pulses. Due to a 10µV
thermal EMF in the test leads, the following Model 2182A measurement conversions
(A/Ds) are made for the first Pulse Delta cycle.
A/D A = 0.01mV
A/D B = 10.01mV
A/D C = 0.01mV
The first Pulse Delta reading (using the 3-point measurement technique) is calculated as
follows:
The above 3-point measurement technique effectively eliminated the 10µV thermal EMF
from the Pulse Delta reading.
2-point measurement technique – Assume for the above example that DUT heating
causes the A/D measurement at point C to be 1.01mV. Using the 3-point measurement
technique, Pulse Delta (by calculation) would instead be 9.5mV. This results in 5% mea-
surement error due to heating.
The affects of heating can be eliminated by not performing the measurement at point C
(low pulse). For this 2-point measurement technique, Pulse Delta is calculated as follows:
PulseDelta
2 B A – C –
2
--------------------------
 
 
1
– ( )
0
• =
2 10.01
( )
0.01
( ) –
0.01
( ) –
2
---------------------------------------------------------------- =
20 mV
2
-------------- =
10 mV
=
PulseDelta
2 B 2 A –
2
--------------------
 
 
1
– ( )
0
• =
2 10.01
( )
2 0.01
( ) –
2
---------------------------------------------- =
20 mV
2
-------------- =
10 mV =