SEA CLUTTERUnwanted echoes from the irregular surface of the sea that appear on a radar indicator
SEARCH RADAR SYSTEMAn early-warning device that searches a fixed volume of space .
SECAS (SHIP EQUIPMENT CONFIGURATION ACCOUNTING SYSTEM)The Navy system that
keeps track of the configuration of equipment in the fleet .
SECONDARYThe output coil of a transformer .
SECONDARY CELLA cell that can be recharged by a current being passed through the cell in a
direction opposite to the discharge current .
SECONDARY EMISSIONThe liberation of electrons from an element, other than the cathode, as a
result of being struck by other high-velocity electrons .
SECONDARY LOOPIn a cooling system, the loop that transfers the heat from the heat source, such as
electronic equipment, to the primary loop; usually distilled water .
SECOND DETECTOR (DEMODULATOR)The part of the receiver that separates the audio or video
component from the modulated intermediate frequency .
SECOND-SWEEP ECHOESSee AMBIGUOUS RETURNS .
SELECTIVITYThe ability of a receiver to select the desired signal and reject unwanted signals  .
SELENIUMA chemical element with light-sensitive properties that makes it useful as a semiconductor
material in metallic rectifiers .
SELF-BIASIn a vacuum tube circuit, the voltage developed by the flow of current through a resistor in
the grid or cathode leads .
SELF-EXCITED GENERATORSDC generators in which the generator output is fed to the field to
produce field excitation .
SELF-EXCITED METERA term used to describe meters that operate from their own power sources
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) The phenomenon
caused by the expanding and collapsing fields of an electron that encircle other electrons and retard the
movement of the encircled electrons .
SELF-LUMINOUS BODIESObjects that produce their own light .
SELF-SYNCHRONIZED RADARA type of radar in which the timing pulses are generated within the
SENDING ENDSee INPUT END .