LOOP AERIAL.--See Aerial, Loop.
LOOSE COUPLED CIRCUITS.--See Circuits, Loose Coupled.
LOUD SPEAKER.--A telephone receiver connected to a horn, or a specially made one, that reproduces the incoming signals, words or music loud enough to be heard by a room or an auditorium full of people, or by large crowds out-doors.
MAGNETIC POLES.--See Poles, Magnetic.
MEGOHM.--One million ohms.
METER, AUDIBILITY.--An instrument for measuring the loudness of a signal by comparison with another signal. It consists of a pair of headphones and a variable resistance which have been calibrated.
MHO.--The unit of conductance. As conductance is the reciprocal of resistance it is measured by the reciprocal ohm or mho.
MICA.--A transparent mineral having a high insulating value and which can be split into very thin sheets. It is largely used in making condensers both for transmitting and receiving sets.
MICROFARAD.--The millionth part of a farad.
MICROHENRY.--The millionth part of a farad.