Keithley 2651A Reference Manual page 53

Model 2651A High Power System SourceMeter® Instrument Reference Manual
When using the Model 2651A as a voltmeter, V-compliance must be set higher than the voltage that
is being measured. Failure to do this could result in excessive current flow into the Model 2651A
(<100 A) and incorrect measurements.
3. Select range: Use the RANGE keys to select a fixed measurement range that will accommodate
the expected reading. Use the lowest possible range for best accuracy. When measuring the
function opposite from the source function, autorange can be used instead. The Model 2651A
automatically goes to the most sensitive range.
4. Connect voltage or current to be measured. Connect the device-under-test (DUT) to the Model
2651A using 2-wire connections (see
5. Press the OUTPUT ON/OFF control to turn the output on.
6. View the displayed reading (press the TRIG key if necessary). When finished, press the OUTPUT
ON/OFF control again to turn the output off.
Ohms measurements
Ohms calculations
Resistance readings are calculated from the measured current and measured voltage as follows:
R = V/I
Where:
R is the calculated resistance
V is the measured voltage
I is the sourced current
Ohms ranging
The front panel ohms function does not use ranging. The unit formats a calculated V/I reading to best
fit the display. There may be leading zeros if the ohms reading is very small (<1 mΩ).
Basic ohms measurement procedure
When using the MODE key to select ohms measurement, the Model 2651A is automatically
configured as a current source with a level of 1 mA. If you wish to change the source function, source
value, or compliance value (in other words, if you wish to customize the MODE key's standard ohm-
meter's configuration), then perform the following steps to perform ohms measurements. The
following procedure assumes that the Model 2651A is already connected to the device-under-test
(DUT) as explained in
2651A-901-01 Rev. A / March 2011
CAUTION
DUT test connections
(on page 2-42).
DUT test connections
Section 2: General operation
(on page 2-42)).
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