LACING SHUTTLE - A device upon which lacing may be wound to prevent fouling the tape or
cord and to aid the lacing process. (Usually made from brass, aluminum, fiber, or plastic)
.
LAG - The amount one wave is behind another in time; expressed in electrical degrees .
LAMINATED CORE - A core built up from thin sheets of metal insulated from each other
and used in transformers .
LAMINATIONS - (see core material.)
LANDS - Conductors or runs on pcbs .
LANGUAGE TRANSLATOR - A program that reads a source program and converts it into an
object (machine language) program. Assemblers and compilers are examples.
LAP WINDING - An armature winding in which opposite ends of each coil are connected to
adjoining segments of the commutator so that the windings overlap .
LARGE SCALE INTEGRATION (lsi) - An integrated circuit containing 1,000 to 2,000 logic
gates or up to 64,000 bits of memory .
LASER - An acronym for light amplification by stimulated emission of radiation .
LATERAL DIRECTION - The direction across the width of the tape.
LAW OF MAGNETISM - Like poles repel; unlike poles attract .
LAYER-TO-LAYER ADHESION - The tendency for adjacent layers of tape in a roll to adhere
to one another.
LAYER-TO-LAYER TRANSFER - The magnetization of a layer of tape in a roll by the field
from a nearby recorded layer, sometimes referred to as print through.
LBE - (See lower band edge.)
LC CAPACITOR-INPUT FILTER - This is the most common type of filter. It is used in a
power supply where output current is low and load current is relatively constant .
LC CHOKE-INPUT FILTER - This filter is used in power supplies where voltage regulation
is important and where the output current is relatively high and subject to varying load
conditions .
LEAD - The opposite of lag. Also a WIRE or CONNECTION .
LEAD-ACID CELL - A cell in an ordinary storage battery in which electrodes are grids of
lead containing an active material consisting of certain lead oxides that change in
composition during charging and discharging. The electrodes or plates are immersed in an
electrolyte of diluted sulfuric acid .
LEAD INDUCTANCE - The inductance of the lead wires connecting the internal components
of an electron tube .
LEAD SHEATH - A continuous jacket of lead molded around a single conductor or multiple
conductor cable. Generally used to ensure conductors are protected from water or extensive
moisture .
LEAKAGE CURRENT - The small amount of current that flows through the dielectric between
the conductors of a transmission line .
LEAKAGE FLUX - Magnetic flux lines produced by the primary winding that do not link the
turns of the secondary winding .
LEAKAGE RESISTANCE - The electrical resistance that opposes the flow of current through
the dielectric of a capacitor. The higher the leakage resistance, the slower the capacitor
discharges or leaks across the dielectric .
LEAST SIGNIFICANT DIGIT (LSD) - The LSD is the digit whose position within a given
number expression has the least weighting power .
LEFT-HAND RULE FOR GENERATORS - A rule or procedure used to determine the direction of
current flow in a generator .
LENZ'S LAW - The current induced in a circuit, caused by its motion in a magnetic field
or a change in it's magnetic flux, in such a direction as to exert a mechanical force
opposing the motion or to oppose the change in flux .
LIGHT-EMITTING DIODE (LED) - A PN-junction diode that emits visible light when it is
forward biased. Depending on the material used to make the diode, the light may be red,
green, or amber .
LIGHTHOUSE TUBE - An electron tube shaped like a lighthouse that is designed to handle
large amounts of power at uhf frequencies .
LIGHT RAYS - Light waves emitting from a source in straight lines .
LIMITER - A device that prevents (limits) a waveform from exceeding a specified value .
LINEAR - Having an output that varies in direct proportion to the input .
LINEAR IMPEDANCE - An impedance in which a change in current through a device changes
in direct proportion to the voltage applied to the device .
LINE OF FORCE - A line in an electric or magnetic field that shows the direction of the
force .
LINE OF SIGHT - Straight line from a radar antenna to a target .
LINE-PULSING MODULATOR - Circuit that stores energy and forms pulses in the same
circuit element, usually the pulse-forming network (pfn) .
LINEARITY - The extent to which the magnitude of the reproduced output is directly
proportional to the magnitude of the signal applied to the input of the recorder.
LIN-LOG AMPLIFIER - An amplifier in which the response is linear for weak signals and
logarithmic for large signals .
LIQUID - One of the three states of matter. It has a definite volume but no definite
form (water is a liquid) .
LIQUID-COOLING SYSTEM - Source of cooling for high-heat producing equipments, such as
microwave components, radar repeaters, and transmitters .
LISSAJOUS PATTERN - A combined, simultaneous display of the amplitude and phase
relationships of two input signals on a CRT .
LOAD - (1) A device through which an electric current flows and which changes
electrical energy into another form. (2) Power consumed by a device or circuit in
performing its function .
LOAD END - See OUTPUT END .
LOADING - See LUMPED-IMPEDANCE TUNING .
LOADING EFFECT - The effect of a voltmeter upon the circuit being measured that results
in an inaccurate measurement. Loading effect is minimized by using a voltmeter with an
internal resistance many times higher than the resistance of the circuit being measured .
LOAD ISOLATOR - A passive attenuator in which the loss in one direction is much greater
than that in the opposite direction. One example is a ferrite isolator for waveguides that
allows energy to travel in only one direction .
LOBE - An area of greater signal strength in the transmission pattern of an antenna .
LOCAL ACTION - A continuation of current flow within a battery cell when there is no
external load. Caused by impurities in the electrode .
LOCAL-AREA NETWORK - A network that normally operates within a well-defined and
generally self-enclosed area. The communication stations or terminals are usually linked
by cable and are within 1,000 feet of each other.
LOGARITHMIC RECEIVER - Receiver that uses a linear logarithmic amplifier (lin-log)
instead of a normal linear amplifier .
LOGIC - The basic principles and applications of truth tables, interconnections of
off-on circuit elements, and other factors involved in mathematical computation in
automatic data processing systems and other devices .
LOGIC CIRCUIT - The primary control information processor in digital equipment; made up
of electronic gates and so named because their operation is described by simple equations
of a specialized logic algebra .
LOGIC CLIPS - A device that can be clipped onto an in-circuit, dual-in-line package
(DIP) logic IC to determine the logic state of each pin of the IC.
LOGIC DIAGRAM - In computers and data processing equipment, a diagram representing the
logical elements and their interconnections without necessarily expressing construction or
engineering details .
LOGIC ELEMENT - The smallest building blocks that can be represented by operators in an
appropriate system of symbolic logic. Typical logic elements are the AND-gate and the
flip-flop, which can be represented as operators in a suitable symbolic logic. Also a
device that performs the logic function .
LOGIC INSTRUCTION - Any instruction that executes a logic operation that is defined in
symbolic logic, such as AND, OR, NAND, or NOR .
LOGIC OPERATION - A nonarithmetical operation in a computer, such as comparing,
selecting, making References, matching, sorting, and merging, where the logical YES or NO
quantities are involved .
LOGIC PROBE - A hand-held probe used to determine the logic state (high or low) of test
points in a logic circuit. A logic high is represented by a lit indicator light on the
probe.
LOGIC PULSER - A hand-held probe used to pulse, or change the logic state, of
in-circuit logic ICs.
LOGIC SWITCH - A diode matrix (See MATRIX) or other switching arrangement that is
capable of directing an input signal to one of several outputs .
LOGIC SYMBOL - A symbol used to represent a logic element graphically. Also a symbol
used to represent a logic operator .
LOGICAL RECORD - A record that includes all the data that belongs together as a unit
regardless of the physical size or storage location of the data.
LONGITUDINAL WAVES - Those waves in which the disturbance (back and forth motion) takes
place in the direction of propagation. Sometimes called compression waves .
LONG-TERM TAPE SPEED - (See tape speed.)
LONG-WIRE ANTENNA - An antenna that is a wavelength or more long at its operating
frequency .
LONGITUDINAL CURVATURE - Any deviation from the straightness of a length of tape.
LOOP - A curved conductor that connects the ends of a coaxial cable or other
transmission line and projects into a waveguide or resonant cavity for the purpose of
injecting or extracting energy .
LOOSE COUPLING - Inefficient coupling of energy from one circuit to another that is
desirable in some applications. Also called weak coupling .
LOOSE DEBRIS - Any material that is very lightly bonded to the tape or the head's top
surface, removable by tape motion.
LOWER BAND EDGE (LBE) - The lower band edge of the recorder/reproducer response
(usually at the -3-dB point).
LOWER-FREQUENCY CUTOFF - The lowest frequency a circuit will pass .
LOWER SIDEBAND - All difference frequencies below that of the carrier .
LOWEST USABLE FREQUENCY - The minimum operating frequency that can be used for
communications between two points .
LOW FREQUENCY - The band of frequencies from 30 kilohertz to 300 kilohertz .
LOW-LEVEL MODULATION - Modulation produced in an earlier stage than the final .
LOW-NOISE AMPLIFIER - See PREAMPLIFIER .
LOW-PASS FILTER - A filter that passes a majority of the low frequencies on to the next
circuit and rejects, or attenuates, the higher frequencies. Also called a high-frequency
discriminator .
LSD - See LEAST SIGNIFICANT DIGIT .
LUMPED CONSTANTS - The properties of inductance, capacitance, and resistance in a
transmission line .
LUMPED IMPEDANCE TUNING - The insertion of an inductor or capacitor in series with an
antenna to electrically lengthen or shorten the antenna .
