AIR CORE TRANSFORMER.--See Transformer, Air Core.
AMATEUR AERIAL OR ANTENNA.--See Aerial, Amateur.
ALTERNATOR.--An electric machine that generates alternating current.
ALPHABET, INTERNATIONAL CODE.--A modified Morse alphabet of dots and dashes originally used in Continental Europe and, hence, called the Continental Code. It is now used for all general public service wireless communication all over the world and, hence, it is called the International Code. See page 305 [Appendix: International Morse Code].
ALTERNATING CURRENT (A.C.)--See Current.
ALTERNATING CURRENT TRANSFORMER.--See Transformer.
AMATEUR GROUND.--See Ground, Amateur.
AMMETER.--An instrument used for measuring the current strength, in terms of amperes, that flows in a circuit. Ammeters used for measuring direct and alternating currents make use of the magnetic effects of the currents. High frequency currents make use of the heating effects of the currents.
AMMETER, HOT-WIRE.--High frequency currents are usually measured by means of an instrument which depends on heating a wire or metal strip by the oscillations. Such an instrument is often called a thermal ammeter, radio ammeter and aerial ammeter.
AMMETER, AERIAL.--See Ammeter, Hot Wire.