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GLOSSARY
A
| Alternating Current (AC) |
a flow of electricity which reaches maximum in one direction,
decreases to zero, then reverses itself and reaches maximum in the
opposite direction. The cycle is repeated continuously. The number
of cycles per second is equal to the frequency. |
| Alternator |
a generator that produces alternating electric current. |
| Ammeter |
an instrument that measures electric current. |
| Ampere |
or amp; A unit that measures the strength/rate of flow of
electrical current. |
| Ampere Hour (Ah) |
is the amount of energy charge in a battery that will allow one ampere of current to flow for one hour. |
B
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| Ballast |
a device used to provide the starting voltage or to stabilize
the current in a circuit. Commonly used for florescent and CFL type
bulbs. |
| Battery |
a device that produces electric current as a result of chemical
reaction. |
| Buss Bar (also Bus Bar) |
separate, metallic strips that extend through the service panel.
Breakers slide onto the "hot" busses. Neutral and ground wires screw
down in their respective busses. |
C
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| Capacitor (condenser) |
a device consisting of two conducting surfaces separated by an
insulator and having the ability of storing electric energy. |
| Circuit Breaker |
the most common type of "over current protection." A breaker
trips when a circuit becomes overloaded or shorts out. |
| Color Rendering Index (CRI) |
an international system used to rate a lamp's ability to render
object colors. The higher the CRI (based upon a 0-100 scale) the
richer colors generally appear. |
| Corona Discharge |
a luminous discharge which occurs when the applied voltage is
high enough (5000 volts or more) to cause partial ionization of the
surrounding gas |
| Current |
a flow of electrons through a conductor. |
D
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| Direct current (DC) |
an electric current that flows in one direction only. |
E
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| Earth |
see "Grounding" |
| Electric Arc |
a discharge of electricity between two electrodes; in effect a
continuous electric spark. |
| Electricity |
the flow of electrons. |
| Electromagnet |
a temporary magnet consisting of a set of coils wound on an iron
core. The device becomes magnetic when electricity is passed through
the coils. |
| ElectroMagnetic Interference (EMI) |
an electromagnetic disturbance that degrades or limits the effective performance of electronic or electrical equipment. |
F
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| Field |
the region around a body where a certain influence is felt, such
as an electric or magnetic field. |
| Floating Ground |
when common connections providing a return grounding path exist, but are not actually connected to an earth ground. |
| Fluoresce |
exhibit or undergo fluorescence - which is light emitted during
absorption of radiation of some other (invisible) wavelength. |
| Frequency |
the number of cycles of alternating voltage or current which
occur during a particular amount of time, usually one second |
| Fuses |
removable devices that link a circuit at the fuse box. Fuse
connections blow apart and break the circuit if an overload or short
occurs. |
G
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| Generator |
an engine that converts mechanical energy into electrical energy
by electromagnetic induction |
| Ground |
A conducting connection between an electrical circuit, or
equipment, and the earth, or to some
conducting body that serves in place of the earth. |
| Ground Fault |
current misdirected from the hot (or neutral) lead to a ground
wire, or any other conducting material. |
| Ground Fault Circuit Interrupter (GFCI or GFI) |
measures the current flowing through the live wire and the
neutral wire. If they differ by more than a few milliamps, the GFI
trips, breaking the circuit. Also called RCD or ELCD. Called a
“Mimsar P’hat" in Hebrew. |
H
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| Hertz (Hz) |
expression of AC frequency in cycles per second, e.g., 50 Hz |
| "Hot" Wire |
slang term used for a live wire. |
I
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| Insulator |
a material that does not conduct electricity |
| Inverter |
a device used to convert direct current into alternating current. |
J
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| Joule |
A unit of electrical energy equal to the work done when a
current of one ampere is passed through a resistance of one ohm for
one second. |
K
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| KW |
kilowatts. |
| Kilowatt-hour (kWh) |
a unit of energy equivalent to one kilowatt of power
operating for one hour. |
L
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| LED |
Light Emitting Diode |
| "Live" Wire |
a wire connected to a power source, having a voltage potential |
| Lumens |
this is a measure of light output from a source, measured in
candlepower. Each lumen represents the brightness of one candle. |
| Lux |
a unit of illumination equal to 1 lumen per square meter. This
is actually measurement of light from a distance. |
M
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| Magnetic Field |
the region around a magnet in which the magnetic forces act. |
N
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| Neutral (O) Wire |
the conductor that is intended to have a ground potential. |
O
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| Ohm |
a unit that measures the resistance a conductor has to
electricity. |
P
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| Photon |
an elementary particle composing light and other forms of
electromagnetic radiation, sometimes called light quantum. |
| Phase |
a factional part of the period of a sinusoidal wave, usually
expressed in electrical degrees. |
| Photoelectric Cell |
a cell whose electrical properties change when light falls on
it. Such cells are used in camera light meters, television camera
tubes, and automatic detection devices. |
| Photovoltaic (PV) Solar Energy |
The word photovoltaic comes from the words photo, meaning light,
and voltaic, meaning electricity. Photovoltaic solar energy uses the
optical light emitted by the sun to produce electricity. |
| Power Factor |
the ratio of true power (watts) to apparent power (volt amps). When these two are identical
(seldom found in an AC circuit) the power factor is 1.0.
The power factor is expressed in decimal or percentage.
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Q
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R
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| Rectifier |
an electrical device that converts alternating current to direct current. |
| Resistance |
the resistance in a substance to the flow of electric current. |
S
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| Sine-Wave |
A uniform wave that is generated by a single frequency. |
| Single-Phase |
an alternating-current circuit consisting of two intentionally
interrelated input terminals, if it’s a load, or two output
terminals, if it’s a source. |
| Solar Cell |
a cell that converts the energy in sunlight into electricity. |
| Spike |
Same as a surge but for a very short period of time
(millisecond), but can measure in the thousands of volts |
| SSL |
Solid State Lighting |
| Star Connection |
see Wye Connection |
| Static Electricity |
the electricity associated with electric charges, which tends to
stay ‘static’ rather than flowing away |
| Surge (electrical) |
surges are an increase in "normal" electrical line voltage.
Usually not more than 500-600 volts. |
| Surge Protector |
a device that shields computer and other electronic devices from
surges in electrical power |
T
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| Three-Phase |
A circuit consisting of three different sine wave current flows,
different in phase by 120 degrees from each other |
| Transformer |
an electrical device used to alter the voltage of alternating
electric current |
U
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| Uninterruptible Power Supply (UPS) |
a device which maintains a continuous supply of electric power to connected equipment by
supplying power from a separate source when utility power is not available. |
V
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| Volt |
the unit of electrical voltage, or "pressure" |
| Volt-ampere (VA) |
a measurement of electrical power in an electrical circuit.
In DC current, 1VA is equivalent of one 1W (watt).
When used with AC current this equation is less precise, because it represents apparent power,
which often differs from true power. |
| Voltage Regulator |
An electrical device that keeps voltage at a constant level
regardless of load fluctuations |
| Voltmeter |
an instrument for measuring the voltage |
W
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| Watt |
a unit that measures the amount of electrical power |
| Wye Connection |
A three-phase winding connection, formed by joining together similar ends of each phase
winding. This point forms the electrical neutral. Also known as
"star connection". |
X
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| XLPE |
Cross-Linked Polyethylene. A thermoset plastic compound that is used for insulation of wire and cable. |
Y
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Z
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| Zero Crossing |
The point at which a sinusoidal voltage or current waveform crosses the zero reference axis. |
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