R - a) Symbol for resistance (see resistance) or resistor. b) 600 volt copper conductor stranded or solid, rubber insulated, cotton braid (rubber filled tape 6 AWG and larger). Cotton braid saturated with moisture resisting, flame-retarding compound smoothly finished. Used for power wiring. c) Abbreviation for riser.
RAD - The unit of measure for a radiation dose which is absorbed, equal to 0.01 joule per kilogram.
RADAR - Acronym for radio detecting and ranging. A system that measures distances and usually the direction to an object by determining the amount of time required for electromagnetic energy to travel to and return from the object.
RADIO - A general term, principally an adjective, applied to the use of electromagnetic waves between 10 KHz and 3 GHz and, in particular, their transmission through space.
RAM EXTRUDER - Wire making machinery for pressure and heat extruding PTFE insulation over a conductor. A predetermined amount of cylindrical shaped molded PTFE powder is placed in a cylinder chamber. A ram is pushed through the cylinder by a jack screw, forcing the PTFE through an orifice or tip through which the conductor is moving and forms a homogeneous tube of insulation around the conductor. The unsintered insulated wire is then passed through a curing oven to complete the process. The limitation of a ram extruder is the size of the slug of preformed PTFE powder. Since it is of constant size, when the slug is exhausted it is the end of the run. It cannot be continuously fed. As the diameter increases, the maximum length of wire to be covered decreases.
RATED TEMPERATURE - The maximum temperature at which an electric component can operate for extended periods without loss of its basic properties.
RATED VOLTAGE - The maximum voltage at which an electric component can operate for extended periods without undue degradation or safety hazard.
REACTANCE - The part of the total impedance of a circuit not due to pure resistance, measured in ohms. Symbol X. It is the imaginary part of the complex impedance,
Z given by:
Z = R +iX
where
R is resistance,
X is reactance and
i equals
.
Reactance is due to the presence of capacitance or inductance in a circuit. The effect of reactance is to cause the voltage and current to become out-of-phase.
RECEIVER - A detector and electronic circuitry to change optical signals to electrical signals.
REEL - Circular container on which wire is wound for storage or transit, usually made of wood or metal.
REFLECTION LOSS - The part of a signal which is lost due to reflection of power at a line discontinuity.
REFLOW SOLDERING - The process of connecting two solder coated conductive surfaces by remelting of the solder to cause fusion.
