Engineering Dictionary of Electronic Terms
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

"R" to "Rad", "Rai" to "Rea", "Rec" to "Relat",
"Relay" to "Resol", "Reson" to "Rh", "Ri" to "Rm", "Ro" to "Rz"

R2R Ladder. A resistor network made by individual resistors or a resistor package. The resistor values are 'R' and 2x 'R' as shown in the graphic. The R2R configuration is also available in resistor SIP or DIP packages.

R2R Network Ladder
R2R Resistor Network

Common resistor values are 1K and 2K, 10 and 20K, 25 and 50K and 50K and 100K providing a wide range of resistance depending on the application.

Race Condition. defines a condition when a device's output depends on two or more nearly simultaneous events to occur at the input. Logic Race Conditions.

Raceway. A channel designed expressly for holding wires, cables, or busbars. Raceways may be of metal or insulating material, and the term includes rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquid-tight flexible metal conduit, flexible metallic tubing, flexible metal conduit, electrical metallic tubing, under-floor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways [also Cable Tray] , and busways. Also refer to MIL-PRF-24758, for flexible weatherproof conduit. A channel or runway with other than circular cross section, designed for protection of electrical wires and/or cables from abrasion, collision, rodents, or other damage. A raceway may have an enclosed cross section, open cross section which may or may not accommodate a cover, or a latching type closure.

Rack. A vertical frame that holds or supports equipment. If the rack uses side panels, than it's called a rack enclosure. Refer to Rack Design. A frame upon which one or more units of equipment are mounted. Related; Equipment Rack Manufacturers.

Rack and Panel Connector. Any of a number of connector styles that are designed to attach to an Equipment Rack, Panel or some other component, normally either square or rectangular shape. An example cable-side, connector is shown to the right.

Radar. An acronym for RAdio Detecting And Ranging.
Refer to the Dictionary of Radar Terms. A radio detection system that transmits short bursts (pulses) of rf energy and detects their echos from objects (targets) such as aircraft or ships.

Radial Lead. A component package that has both leads on the same side of the part, around the central axis. Most components only have two leads on one side, but some four terminal devices have two additional leads on the opposite side of the component. Refer to the graphic to the right.

Radian. [RAD] A unit of plane angle measure equal to the angle subtended at the center of a circle by an arc equal in length to the radius of the circle.

Radiant Energy. Energy in the form of electromagnetic waves.

Radiation. The emission and propagation of energy by means of electromagnetic waves or particles.

Radiation Field. An Antenna Term.

Radiation Hardened. A component that will accept a higher amount of radiation energy either as a Total dose or Single event with out breaking down or failing.

Radiation Hardness Assurance. [RHA] The portion of product assurance, used by the department of defense, which insures that parts continue to perform as specified or degrade in a specified manner when subjected to the specified radiation environmental stress.

Radiation Losses. The losses that occur when magnetic lines of force about a conductor are projected into space as radiation and are not returned to the conductor as the cycle alternates.

Radiation Pattern. The variation of the field intensity of an antenna as an angular function with respect to the axis. Also refer to Antenna Radiation Pattern [Antenna Dictionary].

Radiation Resistance. The resistance that if inserted in place of the antenna would consume the same amount of power as that radiated by the antenna.

Radiation, Space. Radiation from space. Refer to the Space Radiation Dictionary.

Radio. Telecommunication by modulation and radiation of electromagnetic waves.

Radio Communications. The term describing communications over a wireless system.

Radio Frequency. [RF] Any frequency of electromagnetic energy capable of propagation into space. The frequencies that fall between 3 kilohertz and 300 gigahertz used for radio communications. Any frequency within the electromagnetic spectrum normally associated with radio wave propagation.

Radio Frequency Carrier Shift. The system that uses a keyer to shift a radio frequency signal above or below an assigned frequency. These shifts correspond to marks and spaces.

Radio Frequency Choke. A choke designed to impede currents in the RF range.

Radio Horizon. The boundary beyond the natural horizon in which radio waves cannot be propagated over the surface of the earth. The locus of points at which direct rays from an antenna are tangential to the surface of the Earth.

Radio Net. An organization of radio stations that is capable of direct communication on a common frequency.

Radio Set Control Unit. Equipment used to remotely control certain transmitter and receiver functions.

Radio Spectrum. A band of frequencies used for radio communication.

Radio Frequency Spectrum
Radio Spectrum in Frequency and Wavelength

Radiotelephone. A radio as defined in a number of U.S. Federal Regulations [Boating].

Radio Waves. A form of radiant energy that can neither be seen nor felt. An electromagnetic wave that is generated by a transmitter. An electromagnetic wave of a frequency arbitrarily lower than 3000 GHz.

Radix. Also called the base. The number of distinct symbols used in a number system. For example, since the decimal number system uses ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9), the radix is 10. In the binary number system, the radix is 2 because it uses only two symbols (0, 1). Table of Numbering Systems.

Radix Point. Also called Binary Point, Octal Point, Decimal Point and so on, depending on the number system.

Radome. An enclosure designed to protect a radar dish and the measurement equipment used with the dish. In addition to shielding the radar from the weather a radome also conceals the direction the radar is pointing. Refer to the right for a graphic of a radar field.

PC motherboard

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