Other Sources Of Measurement Error - Agilent Technologies 34405A User's And Service Manual

Other Sources of Measurement Error

34405A User's and Service Guide
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Loading Errors (AC volts)
In the AC voltage function, the input of the multimeter appears as a 1 MW
resistance in parallel with 100 pF of capacitance. The cabling that you use
to connect signals to the multimeter also adds capacitance and loading.
For low frequencies, the loading error is:
-100 x R
Error (%) =
R + 1 MΩ
s
At high frequencies, the additional loading error is:
Error (%) =
R = Source Resistance
s
F = Input Frequency
C = Input Capacitance (100 pF) Plus Cable
in
Capacitance
Measurements Below Full Scale
You can make the most accurate AC measurements when the multimeter is
at or near the full scale of the selected range. Autoranging occurs at 10%
(down–range) and 120% (up–range) of full scale. This enables you to
measure some inputs at full scale on one range and 10% of full scale on
the next higher range. In general, the accuracy is better on the lower
range; for the highest accuracy, select the lowest manual range possible for
the measurement.
High Voltage Self Heating Errors
– –
If you apply more than 300 V
internal signal–conditioning components. These errors are included in the
multimeter's specifications.
Temperature changes inside the multimeter due to self–heating may cause
additional error on other AC voltage ranges.
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, self–heating occurs in the multimeter's
rms
Measurement Tutorial
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