Keithley 7021 Instruction Manual page 54

Two-wire resistance tests
Figure 5-5 shows a typical test setup for making two-wire
resistance measurements. The Model 7021 provides the
switching function, while the resistance measurements are
made by a Model 2000 DMM. Since only two-pole switch-
ing is required for this application, one Model 7021 card can
be used to switch up to 30 resistors (additional multiplex
banks can be added, if desired, by adding more cards).
POWER
MODEL 2000 DMM
Figure 5-5
Two-wire resistance testing
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Accuracy of measurements can be optimized by minimizing
stray resistance.
Make connecting wires as short as possible to minimize
path resistance. Another technique is to short one of the
multiplexer inputs, close the shorted channel, and then
enable the DMM zero feature to cancel path resistance.
Leave zero enabled for the entire test.
7021
HI
LO
Single 1x30 MUX
A. Test Configuration
Ω
Model 2000
7021
DMM
B. Simplified Equivalent Circuit
1
1
30
30
DUTs
(30)
R
DUT
Operation
5-7