Definitions E - I
Mass: The mass of a body which is being acted upon by the buoyant
forces of air. The effective mass of a weight is its true mass minus the buoyant force of air displaced by
Effective Value (RMS): The alternating current value that will produce the same amount
of heat in a resistance as the corresponding direct current value.
Efficiency: The ration of useful output energy, usually expressed as a
Effluent: Liquid that has passed through a processing operation.
Elastic Element: The material of which the transducer is constructed, generally
selected for its good elastic properties.
Electrical Relay : Employs a solenoid to provide mechanical action to move a varying
number of electrical contacts back and forth or on and off.
Electronic Switch: An electric circuit designed to cause a start and stop action or
a switching action.
Electrostatic Field: The region surrounding an electric charge in which another charge
experiences a force.
Element: A quality of product, material, or service forming a cohesive
entity on which a measurement or observation may be made.
Empirical: Based on actual measurement, observation, or experience without
regard to science and theory.
Endoergic Reaction: A reaction which absorbs energy.
ERG: A CGS unit of work or energy.
Error (of measurement): The result of a measurement minus the true value of the
Exoergic Reaction: The reaction which liberates energy.
Motor(XPRF): A totally enclosed motor that will withstand an explosion of a
specific vapor or gas within its housing, or will prevent sparks or flashes generated within its housing
from igniting surrounding vapor or gas.
Factory Calibration: The tuning or altering of a control device by the manufacture to
bring it into specification.
Fahrenheit Scale: A temperature scale that defines the freezing point of water as
32 degrees and the boiling point of water a 212 degrees.
Fixed Point: The point where all heat energy applies or removed is used to
change the state of a substance.
Flux: (1) A material used to promote fusion or joining of metals in
soldering, welding, or smelting. (2) A general term used to designate collectively all the electric or
magnetic lines of force in a region.
Device: Any device which a quantitative determination of an applied force
can be made.
Force: A push or pull which produces or prevents motion or has a
tendency to do so.
Forced Vibration: The motion caused by some mechanical excitation.
Free Vibration: Vibration that occurs without forcing.
Frequency Meter: An instrument for measuring the frequency of an AC
Frequency: The number of recurrences of a periodic phenomenon.
Full Scale Output (FSO): The output at rated capacity minus the output at zero applied
Function Tests: Function test often duplicates unit test activities sincefunction
testers do not assume that unit test is adequately done.
Fundamental Method of
Measurement: The method of measurement in which the value of a measurand is
obtained by measurement of the appropriate base quantities.
Fundamental Mode of
Vibration: The lowest natural frequency.
Gage Block: A block of alloy steel with two gaging surfaces.
Gage: A measuring instrument for measuring and indicating a
Gain: Ratio of output voltage, current, or power to input voltage
current or power.
Galvanometer: Meter for detecting or comparing or measuring small electric
Gamma Ray: Electromagnetic radiation emitted during radioactive decay and
having an extremely short wavelength.
Gas: The state of matter that has no definite shape of
Gauge Factor: The sensitivity of the strain gauge.
Gauge Pressure (psig): A measure of the force per area exerted by a fluid using
atmospheric pressure as a zero reference.
Gauss: Unit of magnetic induction.
Go and No Go Gages: Gages that do not measure actual size but merely determine
whether parts are within specified limits.
Grain: A measure of mass in the English gravitational system equal to
Gram: A metric unit of weight equal to one thousandth of a
Gram Atomic Weight: The quantity of an element whose weight in grams is numerically
equal to the atomic weight of the element.
Gram Molecular Weight
(Gram-Mole): The relative molecular weight of a compound, expressed in
Graticule: A network of fine lines, dots, cross hairs, or wires in the focal
plane of the eyepiece of an optical instrument.
Acceleration: The acceleration due to the force of gravity.
Guardband: Also called a frequency guard band, a narrow frequency band
between adjacent channels in multiplexing that is kept unused to prevent the channels from overlapping and
causing crosstalk among modulated signals.
Half Life: The length of time during which half a given number of atoms of a
radioactive element will disintegrate.
Half Thickness: The thickness of absorbing material necessary to reduce the
intensity of radiation by one-half.
HCI: Hydrochloric acid.
Heat of Fusion: The amount of heat needed to melt a unit mass or weight of a
substance at its normal melting point.
Vaporization: Heat required to vaporize a unit mass or weigh of a liquid at
its normal boiling point.
Hertz: The unit of frequency.
Hold Point: Point defined in an appropriate document, beyond which an
activity must not proceed without the approval of a designated organization or authority.
Hunting: The tendency of a mechanical system to oscillate about a normal
condition, or about the point of alignment.
Hydrometer : A measuring instrument for determining the specific gravity of a
liquid or solid.
Hydraulics: Study of liquids in motion.
Hydrostatics: Study of liquids at rest.
Hygrometer: Measuring instrument for measuring the relative humidity of the
Hysteresis: The property of a measuring instrument where its response to a
given stimulus depends of the sequence of preceding stimuli.
Impedance: The opposition in an electric circuit to the flow of an
Index of Refraction: The ratio of the speed of light in a vacuum to its speed in a
Inductive Load: Electrical devices made of wound or coiled wire.
Influence Quantity: Any effect that may influence the uncertainty associated with a
Inertia: The tendency of a body to maintain is state of rest or uniform
motion unless acted upon by an external force.
Infinite: Subject to no limitation or external determination, extending
Initialization: Setting a system to a known state.
Inspection: The process of measuring, examining, testing, gauging, or
otherwise comparing the unit with the applicable instruments.
Attributes: This is inspection whereby either the unit of product is
classified as conforming or nonconforming, or the number of nonconformities in the product is counted, with
respect to a given requirement or set of requirements.
Instability: An undesired change over a period of time, which change is
unrelated to input, operating conditions, or load.
Interferometer: Any measuring instrument that uses interference patterns to make
accurate measurements of waves.
Interpolation: Calculation of the value of a function between the values already
ISO: International Organization for Standardization.
Inversion: The condition that exists when both axes of an image are
Inverter: Any mechanical or electrical device for converting direct current
into alternating current.