Fluke 5502A Operator's Manual page 364

5502A
Operators Manual
true power
The actual power (real power) used to cause heat or work. Compare to "apparent power."
true value
Also named legal value, the accepted, consensus, for example, the correct value of the
quantity that is measured.
uncertainty
The maximum difference between the accepted, consensus, or true value and the
measured value of a quantity. Uncertainty is typically shown in units of ppm (parts per
million) or as a percentage.
units
Symbols or names that specify the measured quantities. Examples of units are: V, mV, A,
kW, and dBm. See also "SI System of Units."
UUT (Unit Under Test)
An abbreviated name for an instrument that is verified or calibrated.
var
Symbol for voltampere reactive, the unit of reactive power, as opposed to real power in
watts.
verification
When the functional performance and uncertainty of an instrument or standard is
examined without adjustments or changes to its calibration constants.
volt
The unit of emf (electromotive force) or electrical potential in the SI system of units. One
volt is the difference of electrical potential between two points on a conductor that
transmitts one ampere of current, when the power being dissipated between these two
points is equal to one watt.
voltage guard
A shield that floats around voltage measurement circuitry inside an instrument. The
voltage guard gives a low-impedance path to ground for common-mode noise and ground
currents. This removes errors introduced by such interference.
watt
The unit of power in the SI system of units. One watt is the power necessary to do work
at the rate of one joule/second. In terms of volts and ohms, one watt is the power
dissipated by one ampere that flows through a one-ohm load.
working standard
A standard that is used in routine calibration and comparison procedures in the laboratory
and is maintained by comparison to reference standards.
zero error
Same as offset error. The indication shown on a meter when an input value of zero is
applied is its zero or offset error.
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