ACCELERATING ANODEAn electrode charged several thousand volts positive and used to
accelerate electrons toward the front of a cathode-ray tube.
ACORN TUBEA very small tube with closely spaced electrodes and no base. The tube is connected to
its circuits by short wire pins that are sealed in a glass or ceramic envelope. The acorn tube is used in
low-power uhf circuits.
AMPLIFICATIONThe ratio of output magnitude to input magnitude in a device intended to produce
an output that is an enlarged reproduction of its input.
AMPLIFICATION FACTORThe voltage gain of an amplifier with no load on the output.
AMPLITUDE DISTORTIONDistortion that is present in an amplifier when the amplitude of the
output signal fails to follow exactly any increase or decrease in the amplitude of the input signal.
AMPERITE (BALLAST) TUBEA current-controlling resistance device designed to maintain
substantially constant current over a specified range of variation in applied voltage or resistance of a
ANODEA positive electrode of an electrochemical device (such as a primary or secondary electric
cell) toward which the negative ions are drawn.
AQUADAG COATINGA special coating of a conductive material, such as graphite, which is applied
to the inside of a CRT. This coating eliminates the effects of secondary emission and aids in the
acceleration of electrons.
BEAM-POWER TUBEAn electron tube in which the grids are aligned with the control grid. Special
beam-forming plates are used to concentrate the electron stream into a beam. Because of this action,
the beam-power tube has high power-handling capabilities.
BRIGHTNESS CONTROLThe name given to the potentiometer used to vary the potential applied to
the control grid of a CRT.
CATHODEThe general name for any negative electrode.
CATHODE BIASThe method of biasing a vacuum tube by placing the biasing resistor in the
common-cathode return circuit, thereby making the cathode more positive with respect to ground.
CATHODE-RAY TUBE (CRT)An electron tube that has an electron gun, a deflection system, and a
screen. This tube is used to display visual electronic signals.
CHOKEAn inductor used to impede the flow of pulsating dc or ac by means of self-inductance.
COLD-CATHODE TUBEA gas-filled electron tube that conducts without the use of filaments. Cold-
cathode tubes are used as voltage regulators.