REFRACTIVE INDEXIn a wave-transmission medium, the ratio between the phase velocity in free
space and in the medium  .
REGENERATIONSee FEEDBACK .
REGENERATIVE DETECTORA detector circuit that produces its own oscillations, heterodynes them
with an incoming signal, and deflects them .
REGENERATIVE FEEDBACKThe process by which a portion of the output signal of an amplifying
device is fed back in phase to reinforce the input. Also called POSITIVE FEEDBACK  .
REGULATORThe section in a basic power supply that maintains the output of the power supply at a
constant level in spite of large changes in load current or input line voltage  .
RELATIVE BEARINGBearing of a target measured in a clockwise direction from "dead ahead" of a
ship or plane .
RELAYAn electromagnetic device with one or more sets of contacts that change position by the magnetic
attraction of a coil to an armature .
RELUCTANCEA measure of the opposition that a material offers to magnetic lines of force .
REMOTE-CUTOFF TUBEAn electron tube in which the control grid wires are farther apart at the
centers than at the ends. This arrangement allows the tube to amplify large signals without being driven
into cutoff. This tube is also called a VARIABLE-MU TUBE .
REPEATER(1) Another name for an active satellite . (2) Also, a common name for remote radar
REPELLERSometimes called a REFLECTOR. An electrode in a reflex klystron with the primary
purpose of reversing the direction of the electron beam .
REPERFORATOREquipment that converts the incoming TTY signal and stores it on paper tape .
REPRODUCTIONThe process of converting electrical signals to sound waves. This sound is speech,
music, and so on .
REPULSIONThe mechanical force tending to separate bodies having like electrical charges or like
magnetic polarity .
RERADIATIONThe reception and retransmission of radio waves that is caused by turbulence in the
RESIDUAL MAGNETISMMagnetism remaining in a substance after removal of the magnetizing force
RESISTANCE(1) The opposition a device or material offers to the flow of current. The effect of
resistance is to raise the temperature of the material or device carrying the current. (2) A circuit element
designed to offer a predetermined resistance to current flow. A resistance of 1 ohm will allow a current
of 1 ampere to flow through it when a potential of 1 volt is applied. .
RESISTIVITYSee SPECIFIC RESISTANCE. The reciprocal of conductivity .