APPENDIX I GLOSSARY

AI-1 APPENDIX I GLOSSARY ACCELERATING ANODE—An electrode charged several thousand volts positive and used to accelerate electrons toward the front of a cathode-ray tube. ACORN TUBE—A 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. AMPLIFICATION—The ratio of output magnitude to input magnitude in a device intended to produce an output that is an enlarged reproduction of its input. AMPLIFICATION FACTOR—The voltage gain of an amplifier with no load on the output. AMPLITUDE DISTORTION—Distortion 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) TUBE—A current-controlling resistance device designed to maintain substantially constant current over a specified range of variation in applied voltage or resistance of a series circuit. ANODE—A positive electrode of an electrochemical device (such as a primary or secondary electric cell) toward which the negative ions are drawn. AQUADAG COATING—A 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 TUBE—An 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 CONTROL—The name given to the potentiometer used to vary the potential applied to the control grid of a CRT. CATHODE—The general name for any negative electrode. CATHODE BIAS—The 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. CHOKE—An inductor used to impede the flow of pulsating dc or ac by means of self-inductance. COLD-CATHODE TUBE—A gas-filled electron tube that conducts without the use of filaments. Cold- cathode tubes are used as voltage regulators.