Impedance - the opposition to flow of an alternating
current resulting from resistance and reactance in a conductor or
component. The reactance changes in magnitude with frequency.
Inrush current - the instantaneous current drawn by an
electrical device at the closing of its switch or at the initial application of
power (can be I OX or more the normal operating current).
Insulation/Isolation resistance - the resistance between
various parts or parts to ground; or between terminals or terminals to ground;
or between groups of parts and terminals or groups of parts/tenninals to
ground. This is usually specified in ohms at a given voltage and frequency
and is typically much greater than I megohm.
Inverter - an electrical equipment (usually electronic)
which is employed to change one form of electrical energy into a form suitable
for a particular/peculiar application within a large system.
Joule - a unit of work energy defined as a watt-second or
the product of power times time.
Kelvin connection - a four terminal circuit by which the
current carrying conductors are isolated from the voltage measurement terminals
to assure accurate measurements of resistance or temperature,
Line regulation - the ability of a power regulator to
maintain its output voltage within specified narrow limits with significant
changes in the magnitude of the input voltage (typically +/-IO% or greater).
Load regulation - a process whereby the output voltage or
current is maintained within specified limits as output load is varied.
This may be specified as static or dynamic regulation.
Load sharing - design techniques whereby multiple power
supplies operating in parallel each supply a share of the load.
Logic Enable/Inhibit - a TTL/CMOS compatible signal
interface to a power supply which can be used to turn it on or off (sometimes
called "remote on/off').
Loop stability - a figure of merit usually given in terms of
phase and gain margins which establish the way to which a control servo responds
to line and load steps.
Low line - the lowest steady-state input voltage for the
operation of to a power supply or power system to remain in specification.
Metal Oxide Varistor (MOV) - usually a zinc oxide pile
component having a non-linear dynamic resistance with voltage, used as a
suppression device to protect against line voltage transients,
Motor Generator - an equipment employed to convert one
frequency or type of energy into another to meet a specific requirement.
It can be AC or DC on either side of the conversion and typically the motor and
generator share a common shaft.
Noise - is normally an unwanted byproduct of the switching
of electrical currents or the result of electromagnetic energy in the
environment. It is usually random but can be synchronous.
N + M - a redundancy technique whereby an extra element(s)
is continuously on-line to become a real-time replacement if one of the elements
constituting N should fail.
Open circuit voltage - the potential appearing across the
output when no current is being drawn.
Output impedance - the impedance (magnitude and phase versus
frequency) when looking back into the circuit. For a change in load
current, there will be a predictable, corresponding change in voltage at a given
Overcurrent protection - circuitry within a power supply
that limits the maximum output current to a specified magnitude.
Overshoot - usually an unwanted result of the sudden
unloading of a current source (i.e., the output of a power supply, which has an
inductor as a part of its output filter). Normally a voltage