18WuD2x

equatorial orbit • equivalent inductance 263
equatorial orbit A satellite orbit that lies in the
plane of the earth’s equator.
equiphase surface Any surface in a wave, over
which the field vectors at a particular instant
have either 0° or 180° phase difference.
equiphase zone The space region in which two radionavigation
signals show no phase difference.
equipment 1. Collectively, apparatus or components
designated for a specific purpose (e.g., radio
equipment). 2. A functional electronic unit,
such as a test instrument, receiver, or memory
unit.
equipment chain A system consisting of seriesconnected
circuits or devices.
equipment ground An electrical ground connection
intended to reduce the chances of electric
shock. An equipment ground does not necessarily
constitute a good radio-frequency ground; it
serves only to eliminate potential differences
among the individual units in a system.
equipment life The period during which electronic
equipment functions according to specifications;
it is terminated at an END POINT.
equipment test A usually preliminary, qualifying
test 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 the
same potential, with respect to the plates.
equipotential surface A surface on which all
points 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 two
distinct signals that are received by aircraft with
equal intensity only in certain directions.
equisignal surface The “surface” around a transmitting
antenna formed by points of equal field
intensity.
equisignal zone The region in which two radionavigation
signals have identical amplitude.
equivalence The condition existing when one network
can be substituted for another without disturbing
currents, impedances, and voltages at
the terminals.
equivalent absorbing power See EQUIVALENT
STOPPING POWER.
equivalent absorption Unit, sabin. The rate at
which a surface absorbs sound energy.
equivalent binary digits For a given decimal number
or specific character, the corresponding binary
digits (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 communications
system.
equivalent capacitance The value of a single
lumped capacitance, that would cause the same
action as the capacitance distributed throughout
a circuit.
equivalent circuit A circuit that has the same
overall current, impedance, phase, and voltage
relationships as a more-complicated counterpart
that it usually replaces for analysis.
equivalent component density For a circuit in
which discrete components are not used or are
not evident, the volume of that circuit divided by
the number of discrete components that would be
required if the circuit used them.
equivalent conductivity The conductivity of a solution
that contains 1 gram equivalent of the solute
in the space between electrodes 1 centimeter
apart.
equivalent dark-input current For a photoelectric
device, the illumination required for an output
current equal to the DARK CURRENT of the device.
equivalent decrement The value of decrement in
a damped wave that would result in the same
amount of interference at a receiver as the interference
caused by the sidebands of an amplitudemodulated
signal.
equivalent delay line A comparatively simple network,
such as a resistance-capacitance (RC) circuit,
that will provide the attenuation and phase
characteristics of an ideal delay line.
equivalent delta In a three-phase system, a deltaconnected
circuit that is equivalent to a given
wye-connected circuit, from the standpoint of
impedance and phase. Also see DELTA CONNEC-
TION and WYE CONNECTION. Compare EQUIV-
ALENT WYE and WYE-EQUIVALENT CIRCUIT.
equivalent differential input capacitance For a
differential amplifier, the equivalent input capacitance
(see EQUIVALENT CAPACITANCE) at one
input (inverting or noninverting) when the opposite
input is grounded.
equivalent differential input impedance For a
differential amplifier, the equivalent input
impedance at one input (inverting or noninverting)
when the other input is grounded.
equivalent differential input resistance For a
differential amplifier, the equivalent input resistance
at one input (inverting or noninverting)
when the other input is grounded.
equivalent equations Two equations for an unknown
that have the same root.
equivalent four-wire system A two-wire line over
which full-duplex operation is obtained by use of
frequency division.
equivalent height See VIRTUAL HEIGHT.
equivalent impedance 1. The value of a single
lumped impedance that would cause the same
action as the impedance distributed throughout a
circuit. 2. An impedance that draws current of
the same strength and phase as that drawn by an
impedance it replaces.
equivalent inductance The value of a single
lumped inductance that would cause the same