The Illustrated Dictionary of Electronics - Loscha

equatorial orbit • equivalent inductance 263equatorial orbit A satellite orbit that lies in theplane of the earth’s equator.equiphase surface Any surface in a wave, overwhich the field vectors at a particular instanthave either 0° or 180° phase difference.equiphase zone The space region in which two radionavigationsignals show no phase difference.equipment 1. Collectively, apparatus or componentsdesignated for a specific purpose (e.g., radioequipment). 2. A functional electronic unit,such as a test instrument, receiver, or memoryunit.equipment chain A system consisting of seriesconnectedcircuits or devices.equipment ground An electrical ground connectionintended to reduce the chances of electricshock. An equipment ground does not necessarilyconstitute a good radio-frequency ground; itserves only to eliminate potential differencesamong the individual units in a system.equipment life The period during which electronicequipment functions according to specifications;it is terminated at an END POINT.equipment test A usually preliminary, qualifyingtest of electronic equipment.equipotential Having a potential difference of zero;being at the same voltage level.equipotential line Between two charged plates,the locus (an imaginary line) of points having thesame potential, with respect to the plates.equipotential surface A surface on which allpoints have the same electrical potential.equisignal Pertaining to signals having equal intensity.equisignal localizer See TONE LOCALIZER.equisignal radio-range beacon For aircraft guidance,a radio-range beacon that transmits twodistinct signals that are received by aircraft withequal intensity only in certain directions.equisignal surface The “surface” around a transmittingantenna formed by points of equal fieldintensity.equisignal zone The region in which two radionavigationsignals have identical amplitude.equivalence The condition existing when one networkcan be substituted for another without disturbingcurrents, impedances, and voltages atthe terminals.equivalent absorbing power See EQUIVALENTSTOPPING POWER.equivalent absorption Unit, sabin. The rate atwhich a surface absorbs sound energy.equivalent binary digits For a given decimal numberor specific character, the corresponding binarydigits (bits).equivalent bit rate The number of binary digits(bits) that can be sent in a given unit of time,such as one second, in a digital communicationssystem.equivalent capacitance The value of a singlelumped capacitance, that would cause the sameaction as the capacitance distributed throughouta circuit.equivalent circuit A circuit that has the sameoverall current, impedance, phase, and voltagerelationships as a more-complicated counterpartthat it usually replaces for analysis.equivalent component density For a circuit inwhich discrete components are not used or arenot evident, the volume of that circuit divided bythe number of discrete components that would berequired if the circuit used them.equivalent conductivity The conductivity of a solutionthat contains 1 gram equivalent of the solutein the space between electrodes 1 centimeterapart.equivalent dark-input current For a photoelectricdevice, the illumination required for an outputcurrent equal to the DARK CURRENT of the device.equivalent decrement The value of decrement ina damped wave that would result in the sameamount of interference at a receiver as the interferencecaused by the sidebands of an amplitudemodulatedsignal.equivalent delay line A comparatively simple network,such as a resistance-capacitance (RC) circuit,that will provide the attenuation and phasecharacteristics of an ideal delay line.equivalent delta In a three-phase system, a deltaconnectedcircuit that is equivalent to a givenwye-connected circuit, from the standpoint ofimpedance and phase. Also see DELTA CONNEC-TION and WYE CONNECTION. Compare EQUIV-ALENT WYE and WYE-EQUIVALENT CIRCUIT.equivalent differential input capacitance For adifferential amplifier, the equivalent input capacitance(see EQUIVALENT CAPACITANCE) at oneinput (inverting or noninverting) when the oppositeinput is grounded.equivalent differential input impedance For adifferential amplifier, the equivalent inputimpedance at one input (inverting or noninverting)when the other input is grounded.equivalent differential input resistance For adifferential amplifier, the equivalent input resistanceat one input (inverting or noninverting)when the other input is grounded.equivalent equations Two equations for an unknownthat have the same root.equivalent four-wire system A two-wire line overwhich full-duplex operation is obtained by use offrequency division.equivalent height See VIRTUAL HEIGHT.equivalent impedance 1. The value of a singlelumped impedance that would cause the sameaction as the impedance distributed throughout acircuit. 2. An impedance that draws current ofthe same strength and phase as that drawn by animpedance it replaces.equivalent inductance The value of a singlelumped inductance that would cause the same