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EUTECTIC SOLDER—An alloy of 63 percent tin and 37 percent lead. Melts at 361º F [14].
EXCITATION VOLTAGE—The supply voltage required to activate a circuit [15].
EXCITING CURRENT—The current that flows in the primary winding of a transformer when the
secondary is open-circuited; it produces a magnetic flux field. Also called magnetizing current [2].
EXCLUSIVE OR—A function whose output is a 1 if one and only one of the input variables is a 1 [13].
EXCLUSIVE-OR GATE—A gate that produces a logic 1 output when the inputs are different, but not
when they are the same [13].
EXPONENT—The numeral written in superscript (102) which indicates the power to which the base is to
be raised [13].
EXPRESSION—A validated series of variables, constants, and functions that can be connected by
operating symbols to describe a desired computation [13].
EXTERNALLY EXCITED METER—A term used to describe meters that get their power from the circuit
to which they are connected [16].
EXTERNALLY SYNCHRONIZED RADAR—A radar system in which timing pulses are generated by a
master oscillator external to the transmitter [18].
EXTREMELY HIGH FREQUENCY—The band of frequencies from 30 gigahertz to 300 gigahertz [17].
EXTREMELY LOW FREQUENCY—The band of frequencies up to 300 hertz [17].
EXTRINSIC—A semiconductor in which impurities have been added to create certain charge carrier
concentrations [7].
FACSIMILE—The method for transmitting and receiving still images. These images can be maps,
photographs, and handwritten or printed text [17].
FACTOR—Any of the elements, quantities, or symbols that, when multiplied together, form a product [13].
FADING—Variations in signal strength by atmospheric conditions [101 [17].
FARAD—The basic unit of capacitance. A capacitor has a capacitance of 1 farad when a voltage potential
of 1 volt across it produces a charge of 1 coulomb [2].
FARADAY ROTATION—The rotation of the plane of polarization of electromagnetic energy when it
passes a substance influenced by a magnetic field that has a component in the direction of propagation
[11].
FAST-TIME-CONSTANT CIRCUIT—Differentiator circuit in the first video amplifier that allows only
the leading edges of target returns, no matter how small or large, to be used [18].
FEEDBACK—The return of a portion of the output of a circuit to its input [8] [18].
FEEDER—A transmission line that carries energy to the antenna [10].
FEEDHORN—A horn radiator used to feed a reflector [18].
FEP—A synthetic type of insulation (fluorinated ethylene propylene) [4].
