Fluke 5790A, Operator'S Manual

Page: 184 / 220

5790A
Operators Manual
A-8
transfer stability
Change in the ac-dc difference correction over time, with stated conditions.
transfer standard
Any standard used to intercompare one measurement or source device with another. Note
that a transfer standard needs only to be stable for the duration of the transfer. It does not
need an assigned value.
transport standard
A transfer standard that is rugged enough to allow shipment by common carrier to
another location.
true value
Also called legal value, the accepted consensus, i.e., the correct value of the quantity
being measured.
uncertainty
The range of values, usually centered on the indicated or requested value, within which
the true, accepted, or consensus value is expected to lie with stated probability or
confidence. Fluke uses 99.7% (3\sigma) confidence limits. Uncertainty is a quantification
of inaccuracy.
units
Symbols or names that define 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 being tested or calibrated.
verification
The comparison of a measurement or source device (UUT) with a measurement or source
device of known and lesser uncertainty, to report variation from required performance.
Verification does not include adjustment or reassignment of values to UUT, and is often
done to determine whether adjustment is necessary. Also see "calibration".
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 carrying
one ampere of current, when the power being dissipated between these two points is
equal to one watt.
watt
The unit of power in the SI system of units. One watt is the power required 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 flowing through a one-ohm load.
wideband
In instrumentation, wideband refers to the ability to measure or generate signals in the
radio frequency spectrum.
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 reading shown on a meter when an input value of zero is
applied is its zero or offset error.