Appendix I Glossary - Cont'd -141200440

ROTARY SWITCH-- A multicontact switch with

PROTECTIVE FEATURE-- The feature of a

component or component part designed to protect

contacts arranged in a circular or semicircular

a component or system from damage.

manner.

PROTECTIVE POTENTIAL-- A term used in

RUSTING-- Corrosion of iron or iron-base alloy to

cathodic protection to define the minimum

form a reddish-brown product known as rust, which

potential required to mitigate or suppress corrosion.

is primarily hydrated iron oxide. A term properly

For steel in quiescent seawater, a value of -0.80 volt

applied only to ferrous alloys.

to Ag/AgCl reference electrode is generally used.

SCALING-- Applying a factor of proportionality to

RECIPROCAL-- The value obtained by dividing the

data or signal levels.

number 1 by any quantity.

SCHEMATIC CIRCUIT DIAGRAM-- A circuit

RECTIFIER-- A device used to convert ac to

diagram in which component parts are represented

pulsating dc.

by simple, easily drawn symbols. May be called

REFERENCE ELECTRODE-- A half-cell of

schematic.

reproducible potential by means of which an

unknown electrode potential can be determined on

SCHEMATIC SYMBOLS-- A letter, abbreviation, or

some arbitrary scale (for example, Ag/AgCl, SCE,

design used to represent specific characteristics or

Cu/CuSO4). A standard against which the

components on a schematic diagram.

potentials of other metal and nonmetallic conductor

SECONDARY-- The output coil of a transformer.

electrodes are measured and compared.

REFERENCE POINT-- A point in a circuit to which

SELF-INDUCTANCE-- The production of a counter

all other points in the circuit are compared.

electromotive force in a conductor when its own

magnetic field collapses or expands with a change

REFERENCE SIGNAL-- The command signal that

in current in the conductor.

requests a specific final condition.

RELAY-- An electromagnetic device with one or more

SELSYN-- Self-synchronizing device or synchro-

sets of contacts that changes contact position by the

motor.

magnetic attraction of a coil to an armature.

SENSING POINT-- A physical and/or functional

RELUCTANCE-- A measure of the opposition that a

point in a system at which a signal maybe detected

material offers to magnetic lines of force.

or monitored in an automatic operation.

REPULSION-- The mechanical force tending to

SENSITIVITY-- (1) For an ammeter, the amount of

separate bodies having like electrical charges or like

current that will cause full-scale deflection of the

magnetic polarity.

meter. (2) For a voltmeter, the ratio of the voltmeter

RESIDUAL MAGNETISM-- Magnetism remaining

resistance divided by the full-scale reading of the

in a substance after removal of the magnetizing

meter, expressed in ohms-per-volt.

force.

SENSOR-- A device that is sensitive to temperature,

RETENTIVITY-- The ability of a material to retain its

pressure, position, level, or speed.

magnetism.

RHEOSTAT-- (1) A resistor whose value can be

SERIES CIRCUIT-- An arrangement where electrical

varied. (2) A variable resistor that is used for the

devices are connected so that the total current must

purpose of adjusting the current in a circuit.

flow through all the devices; electrons have one

path to travel from the negative terminal to the

RLC CIRCUIT-- An electrical circuit that has the

properties of resistance, inductance, and

positive terminal.

capacitance.

SERIES-PARALLEL CIRCUIT-- A circuit that

ROOT MEAN SQUARE (RMS)-- The equivalent

consists of both series and parallel networks.

heating value of an alternating current or voltage,

SET POINT-- The numerical value of a parameter at

as compared to a direct current or voltage. It is 0.707

which an alarm is actuated.

times the peak value of a sine wave.

AI-8