18WuD2x

602 ripple amplitude • Rochelle salt
ring winding
Core
ripple amplitude The peak or peak-to-peak value
of ripple in a power supply (see RIPPLE, 1).
ripple counter A binary counter consisting of flipflops
cascaded in series. A pulse must pass sequentially
from the input, through each stage, to
the output of the chain.
ripple current Current flowing in a circuit as the
result of ripple voltage (see RIPPLE AMPLITUDE).
ripple factor The ratio of the RIPPLE AMPLITUDE
to the direct-current voltage output of a power
supply.
ripple frequency The frequency of a ripple component
(see RIPPLE, 1). In power supplies using
half-wave rectification, this frequency is normally
60 Hz (the line frequency); in full-wave supplies,
it is normally 120 Hz (twice the line frequency).
ripple percentage See PERCENT RIPPLE.
ripple torque Symbol, T R . In a torque motor, the
small fluctuation in torque resulting from commutator
switching action.
ripple voltage See RIPPLE AMPLITUDE.
RISC Abbreviation of REDUCED INSTRUCTION
SET COMPUTER.
rise 1. See VOLTAGE RISE. 2. See RISE TIME.
3. An increase in the amplitude of a pulse or wave.
rise cable 1. A vertical feeder cable. 2. A vertical
section of a feeder cable.
rise time The time required for a pulse to rise from
10 percent to 90 percent of its peak amplitude.
Compare FALL TIME.
RJE Abbreviation of REMOTE JOB ENTRY.
R k Symbol for cathode resistance.
RL 1. Abbreviation of RESISTANCE-INDUCTANCE.
2. Abbreviation of RELAY LOGIC.
R L Abbreviation of LOAD RESISTANCE.
RL bridge See RESISTANCE-INDUCTANCE
BRIDGE.
RL circuit See RESISTANCE-INDUCTANCE CIR-
CUIT.
R LF Symbol for low-frequency resistance.
RL phase shifter See RESISTANCE-INDUCTANCE
PHASE SHIFTER.
R m Symbol for METER RESISTANCE.
r m Symbol for emitter-collector transresistance of a
bipolar transistor.
rms Abbreviation of ROOT MEAN SQUARE.
rms converter See ROOT-MEAN-SQUARE CON-
VERTER.
rms current See EFFECTIVE CURRENT.
rms meter A current meter or voltmeter whose deflection
is proportional to the root-mean-square
(rms) value of current or voltage. In most meters,
the deflection is proportional to either the peak
value or the average value, but the scale of an
rms unit is graduated on the basis of sine-wave
input.
rms value See EFFECTIVE VALUE.
rms voltage See EFFECTIVE VOLTAGE.
Rn Symbol for RADON.
R n 1. Symbol for NEGATIVE RESISTANCE. (Also,
–R.) 2. Symbol for null resistance.
R o Symbol for OUTPUT RESISTANCE. (Also, R out .)
roaming 1. In cellular communications, an ideal
condition in which the user of a mobile or
portable wireless telephone set can travel
throughout a specified geographic region with no
“dead zones” or interruption in service. 2. For a
mobile or portable cellular telephone subscriber,
the act of traveling throughout a large geographic
region and, in particular, among different states
or countries.
robot 1. An electromechanical device or system capable
of reliably performing complex and/or
repetitive tasks. It can be controlled by a human
operator or by a computer. 2. A usually autonomous
device, as defined in 1, built to physically
resemble a human being, with a head, two
arms, and some form of locomotion.
robot generations Agreed-on milestones or criteria
in the evolution of robots and smart machines.
First generation: Before 1980. Mainly
mechanical, stationary, physically rugged, no external
sensors, no artificial intelligence. Second
generation: 1980–1990. Tactile sensors, vision
systems, position sensors, pressure sensors, microcomputer
control, programmable. Third generation:
After 1990. Mobile, autonomy or group
control, artificial intelligence, speech recognition/synthesis,
teleoperation, navigation systems.
Fourth generation: In conceptual stages.
Highly intelligent, capable of building other
robots, capable of doing many human tasks.
robot gripper A robotic END EFFECTOR designed
specifically to grasp objects. The two basic designs
are: hand-like and specialized. Hand-like
grippers are engineered according to the notion
that the human hand has evolved to near perfection,
and should be mimicked in robots. Specialized
grippers are built by trial-and-error methods
and often bear little resemblance to human
hands.
robotics The science and art of robot design, construction,
operation, and maintenance.
Rochelle salt Sodium potassium tartrate, a substance
whose crystals are piezoelectric. Such crystals
are used in some microphones, loudspeakers,
and transducers. Also called SEIGNETE SALT.