L: Electronics: The symbol for inductance.
Lamp Module: See Module, Lamp
LAN: Acronym: Local Area Network; Computers, Networking: A computer network that only covers a small area, such as a single building or set of buildings. Compare to CAN, HAN, MAN, WAN.
Landscape: Computers: A print mode where the image or text is printed sideways, on 11 x 8.5 inch paper, as opposed to Portrait, where the image is printed normally.; Digital Video: An image taken with the camera in its normal horizontal orientation, as opposed to Portrait, where the camera is held sidewise to obtain an image taller than it is wide.
Laser: Acronym: Light Amplification by Stimulated Emission of Radiation; Electronics: A device that generates coherent (all aligned in the same direction) light waves in a single wavelength.
Latitude: Measurement: A position's distance north or south of the equator measured by degrees from zero to 90. One minute of latitude equals one nautical mile.
Lavalier or Lavaliere Microphone: see Microphone, Lavalier or Lavaliere.
LCD: Acronym: Liquid Crystal Display; Electronics: A display screen using liquid crystal technology. There are two primary types of LCD: High-resolution color displays (used in handheld televisions and digital camera/camcorder viewfinders), and monochrome displays using alphanumeric characters on a gray/green/amber background (used in electronic displays of all types).
Lead, Multimeter or Test: see Probe, Multimeter.
Lead-acid: Batteries: A type of battery made up of lead plates immersed in a sulphuric acid electrolyte.
Leakage: Batteries: The unintentional release of chemicals from a battery. Over time, if a battery is stored in a device that is not being used, even “leak-proof” batteries can leak damaging chemicals. If you are not going to use the equipment for some time, always remove the batteries.; Electronics: The undesired flow of electricity around or through a device or circuit.; Electronics, Semiconductors: The current across a reverse biased semiconductor junction.
LEC: Acronym: Local Exchange Company; Telephony: The traditional, local, wired telephone company.
LED: Acronym: Light Emitting Diode; Electronics: A diode that emits visible light when current passes through it. As most LED's operate on a single wavelength, they are generally identified by their size, wavelength and voltage. For example, the 276-086 LED is a 10 millimeter, 660 nanometer, 2 volt (+.2, -.1) Red LED.
Lens: Digital Video: A thin piece of transparent material (usually having a curved surface) that is used to focus the target image onto the image sensor.
LEO: Acronym: Low Earth Orbit; Satellite: An orbit between 200 miles up and 900 miles up, used by satellites.; Communications: An orbital plane a few hundred miles above the earth. A new generation of communications satellites are being launched in this orbit. LEO satellites are generally divided into two groups: big and little LEOs, with each group assigned specific radio frequencies. Big LEOs support both voice and data communications while little LEOs support only data communications.
Letterbox: Video: A wide-screen image on a standard 4:3 aspect ratio television screen, generally seen between black bars above and below the image.
LFE: Acronym: Low Frequency Enhancement; Audio: The subwoofer channel in 5.1 surround systems.
Light Emitting Diode: see LED.
Lighting, Incandescent: DIY, Electronics, Plug 'n Power: Commonly known as the light bulb. Electricity runs through a tungsten filament inside the glass bulb. The filament produces resistance to the electric current and heat is produced. The heat in turn causes the filament to become so hot that is transmits light.
Lightning: Weather: A sudden and visible discharge of electricity produced in response to the build up of electrical potential between cloud and ground, between clouds, within a single cloud, or between a cloud and surrounding air.
Line-level: Audio: A standard audio signal, such as from a CD player or tuner. It has a higher power rating than mic-level.
Liquid Audio: Digital Audio: A producer of software and services to distribute music online.
Liquid Crystal Display: see LCD.
LMDS: Acronym: Local Multipoint Distribution System; Telephony: A system developed by Bellcore for Wireless Local Loop applications that supports voice and high-speed interactive data, with the potential to provide bandwidth of as much as 500 Mbps. In the United States, the FCC set aside a total LMDS bandwidth of 1.15 GHz in the 28 GHz, 30 GHz and 31 GHz frequency bands.
LNB: Acronym: Low Noise Blocker; Satellite: The part of a satellite antenna that is positioned in front of the dish to receive the signal and converts the signal to be carried by cable to the receiver.
LNB Arm: Satellite: The metal arm that physically connects the LNB to the dish.
LNB, Dual: Satellite: An LNB with two output connections.
LNB, Single: Satellite: An LNB with a single output connection.
Load: DIY, Electronics, Batteries: A current draw from a power source (such as a battery or power outlet) or a component or piece of equipment that is connected to a source and draws current from it.
Load, Inductive: Plug 'n Power: Can be defined as inductive reactance and is the characteristic of devices controlled by Plug 'n Power that is not incandescent lighting.
Load, Resistive: Plug 'n Power: Can be referred to as incandescent lighting. Resistance of the electric current in a light bulb filament that produces heat then light gives resistive load its' name.
Local Broadcast: Satellite, Communications: Refers to standard television antennas that are designed to receive signals that are broadcast locally. Also called "off-air" antennas.
Local Exchange Company: see LEC.
Local Multipoint Distribution System: see LMDS.
Lock-out: Communications: To mark a channel on a scanner that is to not be scanned.
Logic Device: see Logic Gate.
Logic Gate: Electronics: The basic component of a integrated circuit, usually with two inputs and one output. There are seven basic logic gates (AND, NAND, NOR, NOT, OR, XNOR and XOR) that compare the inputs and provide an output based on the function of the gate.
Logic Trunked Radio: see LTR.
Longitude: Measurement: The distance east or west of the prime meridian (measured in degrees), which runs from the north to south pole through Greenwich, England. The distance between lines of longitude are greater at the equator and smaller at the higher latitudes, intersecting at the earth's north and south poles. Time zones are correlated to longitude. See also Greenwich Mean Time
Loop: see Search Coil.
Loop Cover: see Scuff Cover.
Loss: Electronics: A decrease in power between the source and the end use. Loss generally occurs in the form of heat.
Lossless: Computer, Digital Audio, Digital Video: A format that stores the data in a non-compressed format, retaining all information.
Lossy: Computer, Digital Audio, Digital Video: A compression format that sacrifices a certain amount of information in order to create a smaller compressed file.
Loudspeaker: Audio: A speaker system which includes the enclosure, the driver or complement of drivers, and the associated electronics, such as a crossover network or internal amplifier.
Low Clouds: see Clouds, Low.
Low Earth Orbit: see LEO.
Low Frequency Enhancement: see LFE.
Low Noise Blocker: see LNB.
Low Pressure System: Weather: an area of a relative pressure minimum that has converging winds and rotates in the same direction as the earth. This is counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. Also known as an cyclone, it is the opposite of an area of high pressure, or an anticyclone.
Low- to Moderate-Discharge Devices: Electronics, Batteries: Devices that draw current from batteries at a lower rate than high-discharge devices. Low- to moderate-discharge devices include (but are not limited to) the following: Scanners, Remote Controls, Portable Radios, any device using the battery for backup (Answering Machines, Clock/Radios). See Premium vs. Standard Batteries for more information.
L-Pad: Audio: A device with two variable impedance pads, developed to provide a constant impedance (generally 8 or 16 ohms) with respect to the amplifier and to control the output level for tweeters and midrange speakers. The L-pad was not intended to be used to control the higher currents of woofers. Because L-pads convert the energy not sent to the speakers into heat, they have largely been replaced by other types of controls, such as transformer-based volume controls.
LTR: Acronym: Logic Trunked Radio; Communications: A method of trunking channel management that gives all users of the system automatic access to all channels, minimizing wait time and making the most efficient use of the available channels. The name is derived from the logic circuitry in the transceivers and repeaters that monitors the system and sends data messages as to which repeaters are free.
Luminance: Video: The black-and-white component of a color video signal. Luminance is the "Y" component in R-Y and B-Y. More properly called Luma.
LZW: Acronym: Lempel-Ziv Welch, named for Jakob Ziv and Abraham Lempel, who proposed the method in 1977 and 1978, and for Terry Welch, who refined the Lempel-Ziv method in 1984.; Digital Video: A compression algorithm used to reduce the size of image files.