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Specifications
Ohms specification calculations (7751/7752/7753)
Ohms specifications for the 7751/7752/7753 module provide the ohms accuracy and tem-
perature coefficient data for specific I-source and V-source output values. The following
formulas can be used to determine the ohms specification for any valid I-source or
V-source output setting not published in the specification sheet.
Ohms accuracy and temperature coefficient are specified as percent of reading plus an
ohms offset.
7751/7752/7753 I-source
Low ohms specifications using the I-source of the 7751/7752/7753 are provided for the
following current output settings: 50mA, 20mA, 10mA, and 1mA (dry circuit ohms). Use
the following formulas for other I-source settings:
klqb
Ohms accuracy
% of reading = (0.07 + 1/ISOURCE) %
Ohms offset = (0.03/ISOURCE) Ω
where: I
Example – Determine ohms accuracy for an I-source setting of 30mA:
% of reading
Ohms offset
Ohms accuracy (30mA) = 0.10% + 1mΩ
The following formulas are only valid when using 1VDC range of the
Model 2790 DMM. When using the SIxOhms math calculation, the 1V range is
selected automatically.
is the current output setting in mA
SOURCE
= (0.07 + 1/30) %
= (0.07 + 0.03) %
= 0.10%
= (0.03/30) Ω
= 1mΩ
Model 2790 SourceMeter Switch System Reference Manual
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