18WuD2x

lug • LZT 423
contact attached to a terminal strip, to which
wire leads are soldered.
lum Abbreviation of LUMEN. The preferred (SI)
form is lm.
lumen Abbreviation, lm, and sometimes l or lum.
The SI unit of luminous flux; it is equal to the
light that is emitted in one steradian (the unit
solid angle) by a uniform point source of one candela.
Also see CANDLE POWER, ILLUMINANCE,
LUMINOUS INTENSITY, SOLID ANGLE, and
STERADIAN.
lumen-hour Abbreviation, lm-hr. The amount of
light that a source having a luminous flux of one
LUMEN delivers in a time period of one hour.
luminaire A complete and self-contained lighting
system, for television-studio use or photographic
use. The kit includes all of the needed parts and
accessories.
luminance The amount of light emitted or scattered
by a surface. This property is expressed in
candelas per square meter (cd/m 2 ).
luminance channel In a color television circuit,
the channel that processes the Y SIGNAL.
luminance signal See Y SIGNAL.
luminescence The production of visible light, but
not heat, by a material stimulated by radiation or
electron bombardment. See ELECTROLUMINES-
CENT CELL and LUMINESCENT SCREEN.
luminescent cell See ELECTROLUMINESCENT
CELL.
luminescent screen A cathode-ray tube whose
screen is coated with a material that glows under
the influence of ionizing radiation, X rays, or electron
beams.
luminiferous ether See ETHER, 1.
luminosity The luminous efficiency of radiant energy,
as given by the ratio of luminous flux to radiant
flux (lumens per watt) for a specific
wavelength.
luminosity factor Abbreviated K, and expressed in
lumens per watt. The luminous intensity divided
by the actual radiant intensity at a given wavelength
of visible light.
luminous energy The energy in visible electromagnetic
radiation.
luminous flux The rate of transfer or flow of luminous
energy.
luminous intensity Luminous flux through a unit
solid angle, expressed in candelas. Also see CAN-
DELA.
lumistor An amplifier or coupling device in which
the input signal varies the brilliance of a lamp,
electroluminescent cell, or light-emitting diode,
and a photocell (or other light-sensitive device)
picks up the fluctuating light and uses it to modulate
an output current. In a compact lumistor,
the light-emitting and light-sensing components
are separate layers in a wafer or block of material.
Compare LIGHT AMPLIFIER.
lumped Pertaining to a property that is concentrated
at or around a single point, rather than be-
Signal
input
Electroluminescent
cell
Light
rays
lumistor
Photoconductive
cell
Load
resistor
Signal
output
ing distributed through a circuit (e.g., lumped capacitance
and lumped inductance).
lumped capacitor See DISCRETE CAPACITOR.
lumped component A discrete component (i.e.,
one that is self-contained). Compare DISTRI-
BUTED COMPONENT.
lumped constant The total value of any single
electrical property in an electrical or electronic
component.
lumped-constant delay line A delay line having discrete
capacitance and inductance components.
Compare DISTRIBUTED-CONSTANT DELAY LINE.
lumped impedance A reactance and/or resistance
manifested in a definite location. Examples are
ordinary components, such as capacitors, inductors,
and resistors.
lumped inductor See DISCRETE INDUCTOR.
lumped parameter Any circuit parameter that can
be considered as a discrete parameter—even if it
is not made up of a single component.
lumped resistor See DISCRETE RESISTOR.
lutetium Symbol, Lu. A metallic element of the
rare-earth group. Atomic number, 71. Atomic
weight, 174.967.
lux The unit of illuminance, equivalent to one LU-
MEN per square meter.
Luxemberg effect The generation of interference
by cross-modulation of two or more signals
whose paths intersect in the same region of the
ionosphere.
luxmeter A device for measuring visible illuminance.
LV Abbreviation of LOW VOLTAGE.
LVDT Abbreviation of LINEAR VARIABLE DIFFER-
ENTIAL TRANSFORMER.
Lw Symbol for LAWRENCIUM; more commonly Lr.
lx Abbreviation of LUX.
L X band A section of the L BAND that extends from
950 MHz to 1.15 GHz.
L Y band A section of the L BAND that extends from
725 to 780 MHz.
L Z band A section of the L BAND that extends from
1.450 to 1.550 GHz.
LZT Abbreviation of LEAD ZIRCONATE-TITANATE,
a ceramic used in electronics.