18WuD2x

400 laser disk • laue diagram
Output
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End
mirror
Substrate and
heatsink
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laser diode
P-type
material
N-type
material
laser disk A method of reproducing sound in
which a laser is used to recover the sound from a
compact disk.
laser Doppler radar Acronyms, ladar or lopplar. A
form of Doppler radar using the light beam of a
laser instead of radio waves.
laser eye surgery A method of repairing the retina
of the eye without cutting the eyeball, using laser
beams to push loose retina tissue back into
place.
laser gun A colloquial term for a weapon that
makes use of a laser as a device of destruction.
laser optical videodisc system A system in which
a low-powered laser reads audio and video information
from a videodisc and delivers it to a television
receiver.
laser ranger A radar-like device using intense light
(instead of microwaves).
laser show A three-dimensional, midair display
having motion, made by using lasers in various
combinations.
laser surgery The application of a laser in
medicine for the purpose of assisting in, or actually
performing, operations on human subjects.
laser welding Welding (especially of tiny pieces)
with the heat produced by a laser beam.
lasing The emission of coherent electromagnetic
energy in the visible-light spectrum. See LASER.
lat Abbreviation of LATITUDE.
latch 1. A feedback loop in a symmetrical digital
circuit, such as a flip-flop, used to maintain a
given state. 2. A simple logic-circuit storage element
that consists of two gates as a unit. 3. To
maintain a closed (energized) state in a pair of relay
contacts after initial energization from a single
electrical pulse. See LATCHING RELAY.
latching current In a thyristor, the minimum
value of anode current (slightly higher than the
holding current) that will sustain conduction immediately
after switch-on.
latching relay An electromechanical or fully electronic
relay that locks into whichever mode it is
energized for (on or off).
latch-on relay See LOCKING RELAY.
latchup In a transistor switching circuit, the abnormal
condition in which the collector voltage
remains at its switched-on level after the transistor
is switched to cutoff from saturation.
latch voltage The input voltage at which a flip-flop
changes states.
late contacts Relay contacts that are operated following
the movement of other contacts during the
relay’s operation.
latency 1. The time taken by a digital computer to
deliver information from its memory. 2. In a serial
storage system, the access time less the word
time.
latent image 1. In a storage tube, a stored image
that is not yet visible. 2. An image stored in the mosaic
of an iconoscope. 3. The image that will appear
when photographic film or paper is developed.
lateral chromatic aberration An aberration affecting
the sharpness of off-axis color television
images.
lateral compliance In phonograph reproduction,
the ease with which the stylus can move laterally
as it follows the groove. Also see COMPLIANCE
and LATERAL RECORDING.
lateral-correction magnet In a color picture tube,
a magnet operated with a set of pole pieces attached
to the focus element of the blue gun; it
controls horizontal positioning of the blue beam
for convergence.
lateral magnet See LATERAL-CORRECTION
MAGNET.
lateral recording A disc recording in which the
groove undulates from side to side. Compare
VERTICAL RECORDING.
latitude Abbreviation, lat. Angular distance measured
around the earth’s circumference to the
north and south from the equator. Compare
LONGITUDE.
latitude effect The tendency of the earth’s magnetic
field to decrease the number of charged
subatomic particles that reach the surface of the
earth near the equator, as compared with the
number reaching the surface at other latitudes.
Latour alternator See BETHENOD ALTERNATOR.
lattice 1. The orderly internal pattern (matrix) of
atoms in a crystal. Also see CRYSTAL LATTICE.
2. A symmetrical arrangement of components in
a network (such as an attenuator, a filter, or a
bridge circuit).
lattice filter A lattice network having reactance in
its arms that makes it a selective circuit.
lattice network See LATTICE, 2.
lattice section See LATTICE, 2.
lattice structure See LATTICE, 1.
lattice winding See UNIVERSAL WINDING.
laue diagram A pattern of spots on a photographic
plate produced by the scattering of high energy
radiation as it falls on a thin crystal. This pattern
is used to determine the nature of the crystal
material.