Keithley 6220 Reference Manual page 174

5-54 Delta, Pulse Delta, and Differential Conductance
Measurement units
The fundamental measurement for Differential Conductance is differential voltage
(dV). However, the dV reading can be converted into a differential conductance
(dG), differential resistance (dR) or power (Watts) reading. See
details on selecting
With Ohms (dR) or Siemens (dG) measurement units selected, the reading is cal-
culated as follows:
dR = dV/dI
dG = dI/dV
With Power measurement units selected, power is calculated using Average Volt-
age and Average Current and is explained in the following paragraphs.
Average Voltage and Power
Average Voltage calculation
Average Voltage is the average bias voltage that was present across the device
when the corresponding Differential Conductance reading was taken. For remote
operation, the Average Voltage reading for Differential Conductance will be
included in the returned data string when the AVOLtage data element is selected.
See "FORMat subsystem," on page 13-4
Average Voltage is calculated as follows:
AvgVolt
AvgVolt
Where: AvgVolt is the Average Voltage corresponding to a given Differential
Power calculation
With WATTS (power) measurement units selected, power for Differential Conduc-
tance is calculated using Average Voltage (see
above) and Average Current.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com
"Measurement
( ) ( )
X + Y Z + Y
------------------ - + ------------------
2 2
= -------------------------------------------- -
2
X + 2Y + Z
= --------------------------- -
4
Voltage (dV) reading.
X, Y and Z are the three A/D measurements for the dV reading.
Return to Section 5 topics
Model 6220/6221 Reference Manual
units".
for details on selecting data elements.
"Average Voltage
page 5-16 for
calculation"