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"

Rocker Switch. A style of mechanical switch that uses a rocking action to turn the switch on and off. A rocker switch may control one or more circuits. Refer here for a listing of Rocker Switch Manufacturers. A rocker switch may be momentary
Panel Mount Rocker Switch
Rocker Switch

Roofing Filter. A low-pass filter used to reduce unwanted higher frequencies.

Root Mean Square. [RMS] The equivalent heating value of an alternating current or voltage, as compared to a direct current or voltage. The DC equivalent is 0.707 times the peak value of a sine wave.

Root-Raised-Cosine Filter. A type of low-pass filter.

Rotary Cap. A spark gap, similar to a mechanically driven rotary switch, used to discharge a pulse forming network.

Rotary Switch. A multi-contact switch with contacts arranged in a circular or semi-circular manner. As the switch is rotated the contacts are engaged or disengaged. Also see the list of Rotary Switch Manufacturers. A switch actuated by a definite angular rotation of the switch shaft about its axis.

Rotating Field. The magnetic field in a multi-phase 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. Motor Manufacturers.

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.

Rotational Latency. The time lapse between a hard drive head reaching the right track, and the hard disk spinning around to the correct sector / block where the data can be read/written by the head.

Rotational Life. The number of revolutions a potentiometer will endure before failure. Expand this definition using the Resistor Dictionary. Although less common; the number of times a rotating switch may be operated before failure [Companies that make Rotary Switches].

Rotations Per Minute. The speed at which an object spins. The speed of a hard disk drive.

Rotor. The revolving part of a rotating electrical machine. The rotor may be either the field or the armature, depending on the design of the machine [Machine Rotor]. The rotating member of a synchro that consists of one or more coils of wire wound on a laminated core. Depending on the type of synchro, the rotor functions similarly to the primary or secondary winding of a transformer. A motor will use either an Armature Rotor or Squirrel Cage Rotor.

Round Conductor. A circular conductor or wire, either solid or stranded wire [multiple wire wrapped into a round conductor]. Not a flat conductor.

Router. In data communications, a functional unit used to interconnect two or more networks.

Routers operate at the network layer (layer 3) of the ISO Open Systems Interconnection. A router reads the network layer address of all packets transmitted by a network, and forwards only those addressed to another network.
Manufacturers of Routers.

WRT300n Router
Wireless Router

RS Flip Flop. See RS Latch.

RS Latch. [Set-Reset Latch] A style of latch where one line sets the latch and the other line resets the latch. Examples include; 74279, 4043, 4044 logic ICs. The SR latch in the graphic uses NAND gates. See also SR NOR gate latch. This type of latch is either called a SR or RS latch, which are used interchangeably.

NAND gate Set-Reset Latch Schematic Diagram
RS Latch

RTD. Resistance Temperature Detector. A device that changes resistance with temperature. Also refer to Thermistor Manufacturers.

Rubidium Clock. A clock containing a quartz oscillator stabilized by a rubidium standard. Sometimes referred to as an Atomic Clock. [Rubidium Oscillator Manufacturers]

Rubidium Standard. A frequency standard in which a specified hyper-fine transition of electrons in rubidium-87 atoms is used to control the output frequency. A rubidium standard consists of a gas cell, which has an inherent long-term instability. This instability relegates the rubidium standard to its status as a secondary standard behind Cesium.

PC motherboard

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