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SEA CLUTTER—Unwanted echoes from the irregular surface of the sea that appear on a radar indicator
[18].
SEARCH RADAR SYSTEM—An early-warning device that searches a fixed volume of space [18].
SECAS (SHIP EQUIPMENT CONFIGURATION ACCOUNTING SYSTEM)—The Navy system that
keeps track of the configuration of equipment in the fleet [16].
SECONDARY—The output coil of a transformer [2].
SECONDARY CELL—A cell that can be recharged by a current being passed through the cell in a
direction opposite to the discharge current [1].
SECONDARY EMISSION—The liberation of electrons from an element, other than the cathode, as a
result of being struck by other high-velocity electrons [6].
SECONDARY LOOP—In a cooling system, the loop that transfers the heat from the heat source, such as
electronic equipment, to the primary loop; usually distilled water [18].
SECOND DETECTOR (DEMODULATOR)—The part of the receiver that separates the audio or video
component from the modulated intermediate frequency [18].
SECOND-SWEEP ECHOES—See AMBIGUOUS RETURNS [18].
SELECTIVITY—The ability of a receiver to select the desired signal and reject unwanted signals [9] [17].
SELENIUM—A chemical element with light-sensitive properties that makes it useful as a semiconductor
material in metallic rectifiers [7].
SELF-BIAS—In a vacuum tube circuit, the voltage developed by the flow of current through a resistor in
the grid or cathode leads [6].
SELF-EXCITED GENERATORS—DC generators in which the generator output is fed to the field to
produce field excitation [5].
SELF-EXCITED METER—A term used to describe meters that operate from their own power sources
[16].
SELF-INDUCTION—(1) The production of a counterelectromotive force in a conductor when its own
magnetic field collapses or expands with a change in current in the conductor [2]. (2) The phenomenon
caused by the expanding and collapsing fields of an electron that encircle other electrons and retard the
movement of the encircled electrons [10].
SELF-LUMINOUS BODIES—Objects that produce their own light [10].
SELF-SYNCHRONIZED RADAR—A type of radar in which the timing pulses are generated within the
transmitter [18].
SENDING END—See INPUT END [10].
