2600AS-901-01 Rev. B / September 2008
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4-17
Series 2600A System SourceMeter® Instruments Reference Manual
Section 4: Source-Measure Concepts
CAUTION
V-Compliance must be set to a level that is higher than the measured
voltage. Otherwise, excessive current will flow into the SourceMeter
instrument. This current could damage the SourceMeter instrument. Also,
when connecting an external voltage to the I-Source, set the output off state
to the high-impedance mode. See “
” earlier in this
section for details.
, the SourceMeter instrument is configured to measure current-only by setting it to
source 0V and measure current. Note that in order to obtain positive (+) readings, conventional
current must flow from IN/OUT HI to LO.
Figure 4-11
Measure only configurations
Contact check
When a contact check measurement is being performed, two small current sources are switched
in between the HI and SENSE HI terminals and the LO and SENSE LO terminals. By controlling
the switches illustrated in
, the current from these sources flows through the test leads
and through the contact resistance as shown. To accurately measure the resulting contact
resistance, the differential amplifier outputs are measured once with the current sources
connected, and again with the current sources disconnected. This allows for compensation of
various offset voltages that can occur.
V-Meter
I-Source
(0.00000
m
A)
A. Measure Voltage Only
IN/OUT HI
IN/OUT
LO
±
DUT (V-Source)
I-Meter
V-Source
(000.000mV)
B. Measure Current Only
IN/OUT HI
IN/OUT
LO
DUT (I-Source)
Positive
Current
Note:
Positive current flowing out of
IN/OUT HI results in positive (+)
measurements.
Note: Use 2-wire local sensing.
