Fluke 5790A, Operator'S Manual

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5790A
Operators Manual
A-2
1. An ac measurement
2. An ac-dc difference measurement
In an ac measurement, the transfer standard is used to determine absolute rms ac voltage
level. In an ac-dc difference measurement, the transfer standard is a reference that tests
the ac and dc response of another transfer standard. The goal of an ac measurement is to
determine the error of the ac source or ac voltmeter under test. The goal of an ac-dc
difference measurement is a value called the "ac-dc difference," which is positive when
more ac voltage than dc voltage is required to produce the same output in the transfer
standard under test.
ac-dc difference
A measurement of an ac-dc transfer device's accuracy. The ac-dc difference is a transfer
device's error when it compares a dc voltage to the same ac rms voltage. A positive ac-dc
difference indicates that more alternating than direct voltage is required to produce the
same reading.
base units
Units in the SI system that are dimensionally independent. All other units are derived
from base units. The only base unit in electricity is the ampere.
buffer
1. An area of digital memory for temporary storage of data.
2. An additional amplifier stage to reduce output impedance levels.
burden voltage
The maximum sustainable voltage across the terminals of a load.
calibration
The comparison of a measurement system or device of unknown accuracy to a
measurement system or device of known and greater accuracy to detect or correct any
variation from required performance of the unverified measurement system or device.
Also see "verification" and "traceability".
calibration constant
A coefficient that is applied manually or automatically to adjust the output or reading of
an instrument.
calibration curve
A smooth curve drawn through a graph of calibration points.
calibration interval
The interval after which calibration must occur to maintain the performance of an
instrument as stated in its specifications.
calibration report
A record of shifts or calibration constant changes that have occurred during calibration.
calibrator
A device that supplies outputs with a known uncertainty for use in testing the accuracy of
measurement devices or other sources.
characterization
A calibration process that produces a calibration constant or known error for use in
correcting the output or reading of an instrument or standard.