18WuD2x

358 impulse relay • inclusive-OR
impulse relay A relay that is able to close or open
completely when driven by a short pulse.
impulse speed The switching rate of a telephone
dialing device as it transmits pulses.
impulse timer A synchronous-motor-driven
timer whose cams can control many circuits; it
can advance by a number of specified increments,
as controlled by an integral stepping
mechanism.
impulse transmission A method of transmission
in which defined impulses are used to denote
changes in signal content or format.
impurity A substance added to an intrinsic semiconductor
to alter its electrical properties.
impurity atom In a processed semiconductor material,
an atom of an IMPURITY material that produces
either n- or p-type properties to the
intrinsic semiconductor.
impurity density In the manufacturing process of
a semiconductor material, the amount of impurity
added to the original semiconductor.
impurity ion In a crystal, an ion in a space between
atoms, or one taking the place of an atom.
impurity level 1. The energy existing in a semiconductor
material as a result of doping (the addition
of an impurity). 2. See IMPURITY
DENSITY.
impurity material See IMPURITY.
IN Abbreviation for INTELLIGENT NETWORK.
In Symbol for INDIUM.
I n Symbol for the nth value of current in a series of
values.
in 1. Abbreviation of INPUT. 2. Abbreviation of
INCH.
inaccuracy 1. The state or condition of instrument
error. 2. The difference between the actual
value of a parameter and the value indicated by
an instrument. 3. The percentage of instrument
error.
inactive leg Within a transducer, an electrical
component whose characteristic remains unchanged
when the stimulus (quantity being
transduced) is applied; specifically, a Wheatstone
bridge element in a transducer.
inactive lines In a conventional television picture,
blanked lines that do not contribute to the visible
part of the image. Approximately half of these
lines are at the top of the screen; the other half
are at the bottom.
inactive time The period during which a radioactivity
counter is insensitive to ionizing agents.
incandescence The state of glowing from intense
heat, as when a metal becomes white hot from an
electric current flowing through it.
incandescent lamp A filament-type lamp. The filament
becomes so hot when an electric current
passes through it that it glows brilliantly.
inch Abbreviation, in. A unit of linear measure in
the English system; 1 in. = 2.54 centimeters =
0.0254 meter.
inching See JOGGING.
inch-pound Abbreviation, in-lb. A unit of work
equal to a force of 1 pound exerted over a distance
of 1 inch. Compare FOOT-POUND.
incident 1. A failure in a computer system requiring
the intervention of an operator in removing or
revising the job involved. 2. Pertaining to a ray or
rays of energy striking a surface or boundary, or
encountering a device (such as an antenna or
photovoltaic cell).
incidental AM Undesired amplitude modulation in
a frequency-modulated signal. Compare INCI-
DENTAL FM.
incident field intensity The field strength of an
electromagnetic field as it arrives at a receiving
antenna.
incidental FM Undesired frequency modulation in
an amplitude-modulated signal. Compare INCI-
DENTAL AM.
incidental time Computer time devoted to other
than program runs or program development.
incident light The light that strikes or enters an
altering device or medium. See INCIDENT RAY.
incident power In a transmission line, the power
that reaches the end of the line. Compare RE-
FLECTED POWER.
incident ray The ray that strikes the surface of a
reflecting, refracting, or absorbing body. Compare
REFLECTED RAY and REFRACTED RAY.
incident wave 1. A wave propagated to the ionosphere.
Compare REFLECTED WAVE and RE-
FRACTED WAVE. Also see IONOSPHERE and
IONOSPHERIC PROPAGATION. 2. A wave that
encounters a change (in density, for example) in a
propagation medium or the transition point between
media.
in-circuit tester An instrument that permits the
checking of components (especially transistors)
without removing them from the circuit in which
they are wired.
inclination 1. At a given geographic location, the
angle between the earth’s magnetic lines of flux
and the horizon. This angle ranges from 0 degrees
at the geomagnetic equator to 90 degrees at the
geomagnetic poles. Compare DECLINATION, 1. 2.
The angle between the plane of a satellite orbit
and the plane containing the equator of the earth,
planet, or star around which the satellite revolves.
Generally measured as the angle at which
the satellite crosses the equator while passing
from the southern hemisphere to the northern
hemisphere. This angle is between 0 and 90 degrees
for satellites in non-retrograde orbits, and
between 90 and 180 degrees for satellites in retrograde
orbits.
inclinometer An instrument for measuring INCLI-
NATION. One form consists of a magnetic needle
mounted so that it can swing inside a vertically
mounted circular scale.
inclusive-OR Also called OR operation. A logical
operation between two operands, the result of
which depends on rules for combining bits in