AMPLIFIER, AUDIO FREQUENCY.--A vacuum tube or other device that amplifies the signals after pa.s.sing through the detector.
AMPLIFIER, MAGNETIC.--A device used for controlling radio frequency currents either by means of a telegraph key or a microphone transmitter. The controlling current flows through a separate circuit from that of the radio current and a fraction of an ampere will control several amperes in the aerial wire.
AMPLIFIERS, MULTI-STAGE.--A receiving set using two or more amplifiers. Also called _cascade amplification_.
AMPLIFIER, VACUUM TUBE.--A vacuum tube that is used either to amplify the radio frequency currents or the audio frequency currents.
AMPLITUDE OF WAVE.--The greatest distance that a point moves from its position of rest.
AMPLIFYING TRANSFORMER, AUDIO.--See _Transformer, Audio Amplifying_.
AMPLIFYING MODULATOR VACUUM TUBE.--See _Vacuum Tube, Amplifying Modulator_.
AMPLIFYING TRANSFORMER RADIO.--See _Transformer, Radio Amplifying_.
ANTENNA, AMATEUR.--See _Aerial, Amateur_.
ANTENNA SWITCH.--See _Switch, Aerial_.
APPARATUS SYMBOLS.--See _Symbols, Apparatus_.
ARMSTRONG CIRCUIT.--See _Circuit, Armstrong_.
ATMOSPHERICS.--Same as _Static_, which see.
ATTENUATION.--In Sending wireless telegraph and telephone messages the amplitude of the electric waves is damped out as the distance increases. This is called _attenuation_ and it increases as the frequency is increased. This is the reason why short wave lengths will not carry as far as long wave lengths.
AUDIO FREQUENCY AMPLIFIER.--See _Amplifier, Audio Frequency_.
AUDIO FREQUENCY AMPLIFICATION.--See _Amplification, Audio Frequency_.
AUDIBILITY METER.--See _Meter, Audibility_.
AUDIO FREQUENCY.--See _Frequency, Audio_.
AUDIO FREQUENCY CURRENT.--See _Current, Audio Frequency_.
AUDION.--An early trade name given to the vacuum tube detector.
AUTODYNE RECEPTOR.--See _Receptor, Autodyne_.
AUTO TRANSFORMER.--See _Transformer, Auto_.
BAKELITE.--A manufactured insulating compound.
B BATTERY.--See _Battery B_.
BAND, WAVE LENGTH.--See _Wave Length Band_.
BASKET WOUND COILS.--See _Coils, Inductance_.
BATTERY, A.--The 6-volt storage battery used to heat the filament of a vacuum tube, detector or amplifier.
BATTERY, B.--The 22-1/2-volt dry cell battery used to energize the plate of a vacuum tube detector or amplifier.
BATTERY, BOOSTER.--This is the battery that is connected in series with the crystal detector.
BATTERY, C.--A small dry cell battery sometimes used to give the grid of a vacuum tube detector a bias potential.
BATTERY, EDISON STORAGE.--A storage battery in which the elements are made of nickel and iron and immersed in an alkaline _electrolyte_.
BATTERY, LEAD STORAGE.--A storage battery in which the elements are made of lead and immersed in an acid electrolyte.
BATTERY POLES.--See _Poles, Battery_.
BATTERY, PRIMARY.--A battery that generates current by chemical action.
BATTERY, STORAGE.--A battery that develops a current after it has been charged.
BEAT RECEPTION.--See _Heterodyne Reception_.
BED SPRINGS AERIAL.--See _Aerial, Bed Springs_.
BLUB BLUB.--Over modulation in wireless telephony.
BROAD WAVE.--See _Wave, Broad_.
BRUSH DISCHARGE.--See _Discharge_.
BUZZER MODULATION.--See _Modulation, Buzzer_.
BLUE GLOW DISCHARGE.--See _Discharge_.
BOOSTER BATTERY.--See _Battery, Booster_.
BROADCASTING.--Sending out intelligence and music from a central station for the benefit of all who live within range of it and who have receiving sets.
CAPACITANCE.--Also called by the older name of _capacity_. The capacity of a condenser, inductance coil or other device capable of retaining a charge of electricity. Capacitance is measured in terms of the _microfarad_.
CAPACITIVE COUPLING.--See _Coupling, Capacitive_.
CAPACITY.--Any object that will retain a charge of electricity; hence an aerial wire, a condenser or a metal plate is sometimes called a _capacity_.
CAPACITY, AERIAL.--The amount to which an aerial wire system can be charged. The _capacitance_ of a small amateur aerial is from 0.0002 to 0.0005 microfarad.
CAPACITY, DISTRIBUTED.--A coil of wire not only has inductance, but also a certain small capacitance. Coils wound with their turns parallel and having a number of layers have a _bunched capacitance_ which produces untoward effects in oscillation circuits. In honeycomb and other stagger wound coils the capacitance is more evenly distributed.
CAPACITY REACTANCE.--See _Reactance, Capacity_.