| The primary advantage of an acoustic lens is that it achieves broader dispersion from a small horn, although it can become beamy at high frequencies and it does reduce on-axis sound level.
Lens mount to Light
Lens mount to Leveluig rod
discs to diffract the sound waves.
Lens mount. The assembly on the front of the camera to which the lens is attached.
Lens speed. Measurement of the ability of a particular lens to collect light; the ability of thallens to work at different light levels; usually expressed by its lowest f/stop number.
Lenz's Law. (Elec.) The direction of an induced current is always such that the magnetic field belonging to it tends to oppose the change in the strength of the magnetic field which is setting up the induced e.m.f.
Leopa,rd-wood. A South American tree used for veneering. The wood is hard and beautifully mottled.
Let-go. (Plast.) An area in laminated glass where intial adhesion between interlay and glass has been lost.
, Let-in. (Shopwk.) A shop term, to signify the sinking in of one portion of wood or metal into another.
Letter board. (Print.) A flat board used as a storage place for composed type. It usually has strips of wood around three edges.
Letter-head. (Print.) The printed form at the head of sheets of latter paper; also the sheet after it is printed.
Letter press. An almost obsolete device for copying letters.
Letter-press printing. (Print.) The making of impressions by means of raised charac ers on type or plates. Letter-size dri s. (Metalwk.) Range from A to Z A is approximately 15.64 in. diameter. Z is approximately 13/3 in. Diameters are expressed in thousandths.
Letter spacin . The extending of a word by pI ing spaces between the letters.
Level. (I) Hori ontal; in a horizontaJ plane. (2) A tool for testing with regard to t e horizontal (Tel.) Power of au io transmission measured in dec bels; also voltage of audio-trans ission measured in V's.
Level indicator. A device which provides a visual display of the signal amplitude. This can be a meter, a series of light emittin diodes (LEOs), etc. Level indicators may respond to the peak, average or RMS value of the signal. A VU meter is a level indicator with a j:arefully specified average response. (See "VU meter'".)
Level match. A term most often describing an adjustment for optimising the signal levels for certain types of compander tape noise reduction systems.
Leveling instrument. (Ellgill.) A device consisting of a sighting
tube with a spirit level so attached that when the bubble is in the
center line, the line of sight is horizontal. A graduatcd arc allows the instru-ment to swing to read angles in the horizontal plane.
Leveling rod. (Sum) There are two general types in common use: target rods and self-reading rods. Tar
Lever to Light bridge
get rods are read only by the rodman,while the self reading rods are read directly by the level man.
Level man.
Lever. (Mech.) A rigid bar turning upon an axis or fulcrum.
Leverage. (Mech.) The mechanical advantage gained through use of a lever.
Lewis. (Arch.) A dovetailed tenon inserted in a heavy stone for the purpose of attachi~g hoisting apparatus.
Lewis bolt. (Bldg.) An. anchor bolt; a bolt having a jagged and taPered tail. It is used for insertion into masonry, where it is held with lead.
Leyden jar. {Elec.} A simple form of condenser. It consists of a glass jar coated with tinfoil inside and out
for a portion of its height and hav- .
ing a brass rod passing through a wooden stopper. This rod makes contact with the inner coating by means of a loose chain.
Liability. The condition of being responsible for a possible or actual loss, penalty, expense, or burden.
Lift. (Aero.) That component of the total air force on an aircraft or air foil perpendicular to the relative wind and in the plane of symmetry.
Must be specified whether this applies to complete aircraft or to its parts. (Print.) A type form every parts is securly locked in the chase
Lifter.A molder tool some times called a cleaner.it derivse the name of lifter from the use to fallen down snad from the bottoms of molds
Lifting magnet. (Elec.) An electromagnet,. carried by a crane hook, which can .lift and deliver masses of iron and steel.
Leydenjar.A device for storing electric charge, consisting essentially of a glass jar lined inside and outside for about two-thirds of its height .with tin foil.
Lift pump. A pump in wltich liquid is lifted rather than forced up from below.
Lift wire. (Aero.) A wire or cable which transmits the strain or lift on the .outer portion of an airplane wing in toward the fuselage or nacelle.
Ligature. (Print.) Two characters or letters joined together on one body as ff, fi, etc.
Light. Electromagnetic radiation to which the organs of sight react, ranging in wavelength from 4,000 to 7,700 angstrom units and is propagated at a speed of about 300 x 1 ()6 meters per second; a similar form of radiant energy that does nto affect the retina, as ultra violet and infrared rays; the sensation produced by stimulation of the organs of sight.
Light bridge. (Tel.) A platform on which lighting controls and at times lights are mounted.
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