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RGK—The symbol used to express the resistance between the grid and the cathode of an electron tube [6].
RHEOSTAT—A variable resistor used for the purpose of adjusting the current in a circuit [1] [4].
RHO—Greek letter "rho" ( ). Used in the field of electricity and electronics to represent the specific
resistance of a substance [4].
RHOMBIC ANTENNA—A diamond-shaped antenna used widely for long-distance, high-frequency
transmission and reception [10].
RIGID COAXIAL LINE—A coaxial line consisting of a central insulated wire (inner conductor) mounted
inside of a tubular outer conductor [10].
RIGIDITY—The tendency of the spin axis of a gyro wheel to remain in a fixed direction in space if no
force is applied to it [15].
RINGING—RF oscillations caused by shock excitation of a resonant circuit or cavity [18].
RING TIME—In radar, the time during which the output of an echo box remains above a specified level
[18].
RIPPLE FREQUENCY—The frequency of the ripple current. In a full-wave rectifier it is twice the input-
line frequency [6].
RIPPLE VOLTAGE—The alternating component of unidirectional voltage. (This component is small
compared to the direct component.) [6]
RLC CIRCUIT—An electrical circuit that has the properties of resistance, inductance, and capacitance [2].
RL DIFFERENTIATOR—An RL circuit in which the output is taken from the inductor [9].
RL INTEGRATOR—An RL circuit in which the output is taken from the resistor [9].
RMS—Abbreviation of root mean square [2].
ROOT MEAN SQUARE (RMS)—The equivalent heating value of an alternating current or voltage, as
compared to a direct current or voltage. It is 0.707 times the peak value of a sine wave [2].
ROTARY CAP—A spark gap, similar to a mechanically driven rotary switch, used to discharge a pulse-
forming network [12].
ROTARY SWITCH—A multicontact switch with contacts arranged in a circular or semicircular manner
[3].
ROTATING FIELD—The magnetic field in a multiphase ac motor that is the result of field windings being
energized by out-of-phase currents. In effect, the magnetic field is made to rotate electrically rather than
mechanically [5].
ROTATING JOINT—A joint that permits one section of a transmission line or waveguide to rotate
continuously with respect to another while passing energy through the joint. Also called a rotary
coupler [11].
