CATCHER GRIDIn a velocity-modulated tube, a grid on which the spaced electron groups induce a
signal. The output of the tube is taken from the catcher grid .
CATHODE(1) In an electron tube the electrode that is the source of current flow . (2) The general
name for any negative electrode . (3) The negative terminal of a forward-biased semiconductor
diode, which is the source of the electrons .
CATHODE BIASThe method of biasing a vacuum tube in which the biasing resistor is placed in the
common-cathode return circuit, thereby making the cathode more positive with respect to ground .
CATHODE KEYINGA system in which the cathode circuit is interrupted so that neither grid current nor
plate current can flow .
CATHODE MODULATORVoltage on the cathode is varied to produce the modulation envelope .
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 .
CATHODE SPUTTERINGA process of producing thin film components .
CAVITY RESONATORA space totally enclosed by a metallic conductor and supplied with energy in
such a way that it becomes a source of electromagnetic oscillations. The size and shape of the enclosure
determine the resonant frequency .
CAVITY WAVEMETERAn instrument used to measure microwave frequencies .
CELLA single unit that transforms chemical energy into electrical energy. Batteries are made up of cells
CENTER-FEED METHODConnecting the center of an antenna to a transmission line which is then
connected to the final (output) stage of the transmitter .
CENTIMETER CUBEA unit of volume of large rectangular or square conductors. The cross-sectional
area equals 1 square centimeter with a length of 1 centimeter .
CHANNELA carrier frequency assignment, usually with a fixed bandwidth .
CHARACTERA letter, digit, or other symbol that is used as part of the organization, control, or
representation of information .
CHARACTERISTIC IMPEDANCEThe ratio of voltage to current at any given point on a transmission
line represented by a value of impedance .
CHARGERepresents electrical energy. A material having an excess of electrons is said to have a
negative charge. A material having a shortage of electrons is said to have a positive charge .
CHARGE CYCLEThe period of time that a capacitor in an electrical circuit is storing a charge .
CHOKEAn inductor used to impede the flow of pulsating dc or ac by means of self-inductance  .
CHOKE JOINTA joint between two sections of waveguide that provides a good electrical connection
without power losses or reflections .
CIRCUITThe complete path of an electric current .