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"F",
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"I",
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"S",
"T",
"U",
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"X",
"Y",
"Z"
Previous set of "S" definitions and terms.
SELECTIVITY. The ability of a receiver to select the desired signal and reject unwanted signals.
SELENIUM. A chemical element with light-sensitive properties that makes it useful as a semiconductor
material in metallic rectifiers.
SELF-BIAS. In a vacuum tube circuit, the voltage developed by the flow of current through a resistor in
the grid or cathode leads.
SELF-EXCITED GENERATORS. DC generators in which the generator output is fed to the field to
produce field excitation.
SELF-EXCITED METER. A term used to describe meters that operate from their own power sources.
SELF-INDUCTION. The production of a counter-electromotive force in a conductor when its own
magnetic field collapses or expands with a change in current in the conductor. 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-SYNCHRONIZED RADAR. A type of radar in which the timing pulses are generated within the
transmitter.
SENSITIVITY. For an ammeter, the amount of current that will cause full-scale deflection of the
meter. For a voltmeter, the ratio of the voltmeter resistance divided by the full-scale reading of the
meter; expressed in ohms per volt. The ability of a receiver to reproduce very weak signals.
The greater the receiver sensitivity, the weaker the signal that can be reproduced. Efficiency of
a microphone. Describes microphone power delivered to a matched-impedance load as compared to the
sound level being converted. Usually expressed in terms of the electrical power level.
Sensor. A device, usually electronic, that extends man's natural senses by means
of emitted or reflected energy. The energy may be nuclear, electromagnetic
including the visible and invisible portions of the spectrum, chemical,
biological, thermal, or mechanical. Sensor Manufacturers
SERIES CIRCUIT. An arrangement where electrical devices are connected so that the total current must
flow through all the devices; electrons have one path to travel from the negative terminal to the positive
terminal.
SERIES-CONNECTED DUPLEXER. A configuration in which the tr spark gap is connected in series in
one leg of the transmission line one-half wavelength away from the T-junction.
SERIES-DIODE DETECTOR. The semiconductor diode in series with the input voltage and the load
impedance. Sometimes called a VOLTAGE-DIODE DETECTOR.
SERIES-FED OSCILLATOR. An oscillator in which dc power is supplied to the amplifier through the
tank circuit or a portion of the tank circuit.
SERIES LIMITER. A diode connected in series with the output, in which the output is taken across the
resistor. Either the positive or negative alternation of the input wave is eliminated.
SERIES-NEGATIVE LIMITER. A diode connected in series with the output, in which the output is
taken across the resistor. It eliminates the negative alternation of the input wave.
SERIES-PARALLEL CIRCUIT. A circuit that consists of both series and parallel networks.
Next page of "S" Terms and definitions
