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8.2. Glossary.
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AC.-
It is nominated as alternating current (abbrevia-
tion in Spanish CA and in English AC) to the electrical
current in which the magnitude and direction varies
in a cyclic way. The most common wave shape of the
alternating current is sinewave, because the energy
transmission is better. Nevertheless, some applications
could need other period wave shapes, like triangular or
square.
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Bypass.-
Manual or automatic, it is the physical junction be-
tween the input and the output electric device.
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DC.-
The direct current (CC in Spanish, DC in English) is the
continuous electron flow through a cable between two points
with different potential. Unlike the alternating current, in direct
current the electrical loads always flow in the same direction
from the highest potential point to the lowest one. Although,
usually the direct current is identified with the constant cur-
rent (for example the one supplied by the battery), it is con-
tinuous any current that always maintain the polarity.
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DSP.-
It is the acronym of Digital Signal Processor. A DSP is
a system based on a processor or microprocessor that has
instructions in it, a hardware and an optimised software to
develop applications where numerical operations are needed
with very fast speed. Due to this, it is very useful to process
analogical signals in real time: in a system that runs in this
way (real time) samples are received, usually coming from an
analogical/digital converter(ADC).
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Power factor.-
It is defined as power factor, p.f., of an alter-
nating current circuit, as the ratio between the active power,
P, and the apparent power, S, or as the cosines of the angle
that make the current and voltage vectors, designating as
EQU DGKPI VJGXCNWGQHVJCVCPING
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GND.-
The term ground, as its name states, refers to the po-
tential of the earth surface.
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EMI filter.-
Filter able to decrease the electromagnetic inter-
ferences, which is the perturbation that happens in a radio
receptor or in any other electrical circuit caused by the elec-
tromagnetic radiation coming from an external source. Also
it is known as EMI, ElectroMagnetic Interference, Radio Fre-
quency Interference or RFI. This perturbation can derate or
limit the efficiency of the circuit.
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IGBT.-
The Insulated Gate Bipolar Transistor is a semicon-
ductor device that is used as a controlled switch in power
electronic circuits. This device has the feature of the gate
signal of the effect field transistors with the capacity of high
current and low voltage saturation of the bipolar transistor,
combining an isolated FET gate for the input and a bipolar
transistor as switch in a single device. The triggering circuit
of the IGBT is as the MOSFET one, while the driving features
are like the BJT.
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Interface.-
In electronic, telecommunications and hardware,
an interface (electronic) is the port (physical circuit) through
which are sent or received signals from a system or subsys-
tems toward others.
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kVA.-
The voltampere is the unit of the apparent power in
electrical current. In direct current is almost equal to the real
power but in alternating current can defer depending on the
power factor.
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LCD.-
LCD acronym of Liquid Crystal Display, device in-
vented by Jack Janning, who was employee of NCR. It is an
electric system of data presentation based on 2 transparent
conductor layers and in the middle a special crystal liquid that
have the capacity to orientate the light when trespassing.
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LED.-
LED acronym of Light Emitting Diode, is a semicon-
ductor device (diode) that emits light almost monochrome
with a very narrow spectrum, it means, when it is direct polar-
ized and it is crossed by an electric current. The colour, (wave
longitude), depends on the semiconductor material used in
its construction, being able to vary from the ultraviolet one,
going through the visible spectrum light, to the infrared, re-
ceiving these last ones the denomination of IRED (Infra Red
Emitting Diode).
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Circuit breaker.-
A circuit breaker or switch, is a device
ready to break the electrical current of a circuit when it over-
comes the maximum set values.
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On-Line mode.-
Regarding to an equipment, it is on line
when it is connected to the system, and it is in operation, and
usually has its power supply turned on.
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Inverter.-
An inverter, is a circuit used to convert direct cur-
rent into alternating current. The function of an inverter is to
change an input voltage of direct current into a symmetrical
output voltage of alternating current, with the required magni-
tude and frequency by the user or the designer.
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Rectifier.-
In electronic, a rectifier is the element or circuit
that allows to convert the alternating current into direct cur-
rent. This is done by rectifier diodes, which can be solid state
semiconductors, vacuum or gassy valves as the mercury
vapour. Depending on the features of the alternating current
power supply used, it is classified as single phase, when they
are fed by a single phase electrical mains, or three phase
when they are fed by the three phases. Depending on the
rectification type, they can be half wave, when only one of the
current semi-cycles is used, or full wave, where both semi-
cycles are used.
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Relay.-
The relay(in French relais, relief) is an electrome-
chanical device that works as a switch controlled by an elec-
tric circuit where, through an electromagnet, a set of contacts
are moved and it allows to open or to close other independent
electric circuits.
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SCR.-
Abbreviation of «Silicon Controlled Rectifier», called
commonly as Thyristor: semiconductor device of 4 layer that
works as almost an ideal switch.
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THD.-
They are the acronyms of «Total Harmonic Distor-
tion». The total harmonic distortion is done when the output
signal of a system is not equivalent to the one that enter into
it. This lack of linearity affects to the wave shape, because
the equipment has introduced harmonics that they were not
in the input signal. As they are harmonics, it means multiple
of the input signal, this distortion is not so dissonant and it is
more difficult to detect.
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