Fluke 5790A Service Manual page 324

5790A
Service Manual
AC-DC Transfer
The process of comparing an AC voltage to a known DC voltage, thereby transferring the
low uncertainty of the DC voltage to the AC voltage. The 792A can be used to perform
two different types of AC-DC transfers:
1. An AC measurement
2. An AC-DC difference measurement
In an measurement, the transfer standard is used to determine absolute RMS voltage
level. In an AC-DC difference measurement, the transfer standard is a reference that tests
the and DC response of another transfer standard. The goal of an measurement is to
determine the error of the source or voltmeter under test. The goal of an AC-DC
difference measurement is a value called the "AC-DC difference", which is positive
when more 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 cury. The AC-DC difference is a transfer
device's error when it compares a DC voltage to the same 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 ross the terminals of a load.
Calibration
The comparison of a measurement system or device of unknown cury to a measurement
system or device of known and greater cury to detect or correct any variation from
required performance of the unverified measurement system or device. Also see
"verification" and "treability".
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.
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