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Errors Due to
Leadwire Resistance
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The resistance of leadwires in series with an
active strain gage attenuates the bridge output (or
"desensitizes" the gage) by the factor:
where:
= total resistance of leadwires in series with the
gage (two lengths of leadwire for a two-wire-circuit,
and one length for a three-wire circuit)
= gage resistance.
The error,
e
, caused by leadwire resistance can be expressed as:
When the leadwire resistance is known
, indicated strains can be corrected for leadwire
effects by multiplying the strains by:
As an alternative to correcting the data
numerically, the gage factor of the strain indicator
can be adjusted from its original value,
, to a new, compensating value,
, where
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