Section 3
TM9211B-A-00
6 November 2013
3-5
Note: Most readout instruments, have a residual error at the low end of their range which may
be a significant accuracy factor. Examine the specifications of the milli-voltmeter used to
determine what these errors are. For this reason it is good instrumentation practice to use that
shunt range which will provide the highest millivolt output for a given current flow. As an
example, if the 10 A range is being used for measurements of 1 A or below, change to the 1 A
range. Higher accuracy can be achieved by using the deviation from nominal data provided on
the certificate of calibration."
3.3
Additional Applications of the Model 9211B
Each shunt can be employed as a separate 4 terminal standard resistor for measurements of
resistance. The operating procedure is identical to that described previously. The circuit would
include a resistance in series with the "current" connections rather than an instrument under test
(although it could include both if desired). By measuring the voltage drop separately across the
resistance under test the two resistors can he compared.
Note: When comparing standard resistors as described above, accuracy of comparison is directly
proportional to current stablity if using a single milli-voltmeter to measure the drop across each
resistor and switching from the standard to the unit under test. If two milli-voltmeters are
employed overall accuracy must include the accuracy of both readout instruments.
Summary of Contents for 9211B Series
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