Fluke 5820A, Руководство оператора

Страница: 241 / 272

Appendices
Glossary
A
A-7
scale error
Same as gain error. Scale or gain error results when the slope of the meter’s response
curve is not exactly 1. A meter with only scale error (no offset or linearity error), will
read 0 V with 0 V applied, but something other than 10V with 10V applied.
secondary standard
A standard maintained by comparison against a primary standard.
sensitivity
The degree of response of a measuring device to the change in input quantity, or a figure
of merit that expresses the ability of a measurement system or device to respond to an
input quantity.
shield
A grounded covering device designed to protect a circuit or cable from electromagnetic
interference.
SI System of Units
The accepted International System of Units. See also “units,” “base units,” and “derived
units.”
specifications
A precise statement of the set of requirements satisfied by a measurement system or
device.
stability
A measure of the freedom from drift in value over time and over changes in other
variables such as temperature. Note that stability is not the same as uncertainty.
standard
A device that is used as an exact value for reference and comparison.
standard cell
A primary cell that serves as a standard of voltage. The term “standard cell” often refers
to a “Weston normal cell,” which is a wet cell with a mercury anode, a cadmium mercury
amalgam cathode, and a cadmium sulfate solution as the electrolyte.
systematic errors
Errors in repeated measurement results that remain constant or vary in a predictable way.
temperature coefficient
A factor per
°
C deviation from a nominal value or range that the uncertainty of an
instrument increases. This specification is necessary to account for the thermal
coefficients in a calibrator’s analog circuitry.
test uncertainty ratio
The numerical ratio of the uncertainty of the measurement system or device being
calibrated to the uncertainty of the measurement system or device used as the calibrator.
(Also called “test accuracy ratio.”)
thermal emf
The voltage generated when two dissimilar metals joined together are heated.