EUTECTIC SOLDERAn alloy of 63 percent tin and 37 percent lead. Melts at 361º F .
EXCITATION VOLTAGEThe supply voltage required to activate a circuit .
EXCITING CURRENTThe 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 .
EXCLUSIVE ORA function whose output is a 1 if one and only one of the input variables is a 1 .
EXCLUSIVE-OR GATEA gate that produces a logic 1 output when the inputs are different, but not
when they are the same .
EXPONENTThe numeral written in superscript (102) which indicates the power to which the base is to
be raised .
EXPRESSIONA validated series of variables, constants, and functions that can be connected by
operating symbols to describe a desired computation .
EXTERNALLY EXCITED METERA term used to describe meters that get their power from the circuit
to which they are connected .
EXTERNALLY SYNCHRONIZED RADARA radar system in which timing pulses are generated by a
master oscillator external to the transmitter .
EXTREMELY HIGH FREQUENCYThe band of frequencies from 30 gigahertz to 300 gigahertz .
EXTREMELY LOW FREQUENCYThe band of frequencies up to 300 hertz .
EXTRINSICA semiconductor in which impurities have been added to create certain charge carrier
FACSIMILEThe method for transmitting and receiving still images. These images can be maps,
photographs, and handwritten or printed text .
FACTORAny of the elements, quantities, or symbols that, when multiplied together, form a product .
FADINGVariations in signal strength by atmospheric conditions [101 .
FARADThe 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 .
FARADAY ROTATIONThe 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
FAST-TIME-CONSTANT CIRCUITDifferentiator circuit in the first video amplifier that allows only
the leading edges of target returns, no matter how small or large, to be used .
FEEDBACKThe return of a portion of the output of a circuit to its input  .
FEEDERA transmission line that carries energy to the antenna .
FEEDHORNA horn radiator used to feed a reflector .
FEPA synthetic type of insulation (fluorinated ethylene propylene) .