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2600AS-900-01 Rev. B / September 2008
Appendix A: Frequently Asked Questions
Series 2600A System SourceMeter
Figure A-4
Connecting channels in parallel for higher current
How do I make contact check measurements?
Contact check connections
The contact check function prevents measurement errors due to excessive resistance in the force
or sense leads caused by poor contact at the DUT, failing relay contacts on a switching card, or
wires that are too long or thin. The contact check function will also detect an open circuit that may
occur with a four-point probe is misplaced or misaligned.
shows Model 2601A/2602A/
2611A/2612A contact check connections, and
shows Model 2635A/2636A contact
check connections. R
C
is the resistance of the mechanical contact at the DUT, and R
S
is the series
resistance of relays and cables.
Figure A-5
Model 2601A/2602A/2611A/2612A contact check connections
Chan B
Chan A
2602A #1,
2612A #1,
or
2636A #1
+
+
Chan B
Chan A
2602A #2,
2612A #2,
or
2636A #2
+
+
DUT
I
1
I
2
I
3
I
4
I
T
= I
1
+ I
2
+ I
3
+1
4
S LO
LO
CHANNEL A
LO
G
LO
HI G G G HI
S
S
KEITHLEY Model 2601A/2602A/2611A/2612A
HI
S HI
DUT
R
S
R
S
R
S
R
S
R
C
R
C
R
C
R
C
Cable/relay
resistance
Contact
resistance