Electrical Engineers design complex
power systems...
... and electronic
circuits.
Electrical engineering, sometimes referred to as
electrical and electronic engineering, is a field
of
engineering that deals with the study
and application of
electricity,
electronics and
electromagnetism. The field first became an
identifiable occupation in the late nineteenth century after
commercialization of the electric
telegraph and electrical power supply. It now
covers a range of subtopics including
power,
electronics,
control
systems,
signal processing and
telecommunications.
Electrical engineering may or may not include
electronic engineering. Where a
distinction is made, usually outside of the United States,
electrical engineering is considered to deal with the problems
associated with large-scale electrical systems such as
power transmission and
motor control, whereas electronic
engineering deals with the study of small-scale electronic systems
including
computers and
integrated circuits. Alternatively,
electrical engineers are usually concerned with using electricity
to transmit energy, while electronic engineers are concerned with
using electricity to transmit information.
History
Electricity has been a subject of
scientific interest since at least the early 17th century. The
first electrical engineer was probably
William Gilbert who designed the
versorium: a device that detected the presence of
statically charged objects. He was also the first to draw a clear
distinction between magnetism and static electricity and is
credited with establishing the term electricity. In 1775
Alessandro Volta's scientific
experimentations devised the
electrophorus, a device that produced a static
electric charge, and by 1800 Volta developed the voltaic pile, a
forerunner of the electric battery.
However, it was not until the 19th century that research into the
subject started to intensify. Notable developments in this century
include the work of
Georg Ohm, who in 1827
quantified the relationship between the
electric current and
potential difference in a conductor,
Michael Faraday, the discoverer of
electromagnetic induction
in 1831, and
James Clerk
Maxwell, who in 1873 published a unified
theory of electricity and
magnetism in his treatise
Electricity and
Magnetism.
During these years, the study of electricity was largely considered
to be a subfield of
physics. It was not
until the late 19th century that
universities started to offer
degrees in electrical engineering.
The
Darmstadt University of
Technology
founded the first chair and the first faculty of
electrical engineering worldwide in 1882. In the same year,
under Professor Charles Cross, the Massachusetts
Institute of Technology
began offering the first option of Electrical
Engineering within a physics department. In 1883 Darmstadt
University of Technology and Cornell University
introduced the world's first courses of study in
electrical engineering, and in 1885 the University
College London
founded the first chair of electrical engineering
in the United Kingdom. The University of Missouri
subsequently established the first department of
electrical engineering in the United States in 1886.
During this period, the work concerning electrical engineering
increased dramatically. In 1882,
Edison switched on the world's first
large-scale electrical supply network that provided 110 volts
direct current to fifty-nine
customers in lower Manhattan. In 1884
Sir Charles Parsons invented the
steam turbine which today generates
about 80 percent of the
electric
power in the world using a variety of heat sources. In 1887,
Nikola Tesla filed a number of patents
related to a competing form of power distribution known as
alternating current. In the following
years a bitter rivalry between Tesla and Edison, known as the
"
War of Currents", took place over
the preferred method of distribution. AC eventually replaced DC for
generation and power distribution, enormously extending the range
and improving the safety and efficiency of power
distribution.
The efforts of the two did much to further electrical
engineering—Tesla's work on
induction
motors and
polyphase systems
influenced the field for years to come, while Edison's work on
telegraphy and his development of the
stock
ticker proved lucrative for his company, which ultimately
became
General Electric. However,
by the end of the 19th century, other key figures in the progress
of electrical engineering were beginning to emerge.
Modern developments
During the
development of radio,
many scientists and
inventors contributed
to
radio technology and electronics. In his
classic
UHF experiments of
1888,
Heinrich Hertz transmitted (via
a
spark-gap transmitter) and
detected
radio waves using electrical
equipment. In 1895, Nikola Tesla was able to detect signals from
the transmissions of his New York lab at West Point (a distance of
80.4 km / 49.95 miles). In 1897,
Karl Ferdinand Braun introduced the
cathode ray tube as part of an
oscilloscope, a crucial enabling
technology for
electronic television.
John Fleming invented the first
radio tube, the
diode, in 1904. Two years
later,
Robert von Lieben and
Lee De Forest independently developed
the amplifier tube, called the
triode.In
1895,
Guglielmo Marconi furthered
the art of hertzian wireless methods. Early on, he sent wireless
signals over a distance of one and a half miles. In December 1901,
he sent wireless waves that were not affected by the curvature of
the Earth. Marconi later transmitted the wireless signals across
the Atlantic between Poldhu, Cornwall, and St. John's,
Newfoundland, a distance of .In 1920
Albert
Hull developed the
magnetron
which would eventually lead to the development of the
microwave oven in 1946 by
Percy Spencer.
In 1934 the British military began to make
strides toward radar (which also uses the
magnetron) under the direction of Dr Wimperis, culminating in the
operation of the first radar station at Bawdsey
in August
1936.
In 1941
Konrad Zuse presented the
Z3, the world's first fully functional
and programmable computer.
In 1946 the ENIAC
(Electronic
Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing
era. The arithmetic performance of these machines allowed
engineers to develop completely new technologies and achieve new
objectives, including the
Apollo
missions and the
NASA moon
landing.
The invention of the transistor in 1947 by
William B. Shockley,
John
Bardeen and
Walter Brattain
opened the door for more compact devices and led to the development
of the
integrated circuit in 1958
by
Jack Kilby and independently in 1959
by
Robert Noyce.
Starting in 1968,
Ted Hoff and a team at Intel
invented the
first commercial microprocessor,
which presaged the personal
computer. The
Intel 4004 was a
4-bit processor released in 1971, but in 1973 the
Intel 8080, an 8-bit processor, made the first
personal computer, the
Altair 8800,
possible.
Education
Electrical engineers typically possess an
academic degree with a major in electrical
engineering. The length of study for such a degree is usually four
or five years and the completed degree may be designated as a
Bachelor of Engineering,
Bachelor of Science,
Bachelor of Technology or
Bachelor of Applied Science
depending upon the university. The degree generally includes units
covering
physics,
mathematics,
computer science,
project management and
specific topics in
electrical engineering. Initially such topics cover most, if
not all, of the sub-disciplines of electrical engineering. Students
then choose to specialize in one or more sub-disciplines towards
the end of the degree.
Some electrical engineers also choose to pursue a postgraduate
degree such as a
Master of
Engineering/
Master of Science
(MEng/MSc), a Master of
Engineering Management, a
Doctor of Philosophy (PhD) in
Engineering, an
Engineering
Doctorate (EngD), or an
Engineer's
degree. The Master and Engineer's degree may consist of either
research,
coursework or a mixture of the two. The Doctor of
Philosophy and Engineering Doctorate degrees consist of a
significant research component and are often viewed as the entry
point to
academia. In the United Kingdom
and various other European countries, the
Master of Engineering is often
considered an undergraduate degree of slightly longer duration than
the
Bachelor of
Engineering.
Practicing engineers
In most countries, a Bachelor's degree in engineering represents
the first step towards
professional certification and
the degree program itself is certified by a
professional body. After completing a
certified degree program the engineer must satisfy a range of
requirements (including work experience requirements) before being
certified.
Once certified the engineer is designated the
title of Professional Engineer
(in the United States, Canada and South Africa ), Chartered Engineer (in India, the United
Kingdom, Ireland and Zimbabwe
), Chartered Professional
Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).
The advantages of certification vary depending upon location. For
example, in the United States and Canada "only a licensed engineer
may seal engineering work for public and private clients".
This
requirement is enforced by state and provincial legislation such as
Quebec's
Engineers Act. In other countries, no such
legislation exists. Practically all certifying bodies maintain a
code of ethics that they expect all
members to abide by or risk expulsion. In this way these
organizations play an important role in maintaining ethical
standards for the profession. Even in jurisdictions where
certification has little or no legal bearing on work, engineers are
subject to
contract law. In cases where
an engineer's work fails he or she may be subject to the
tort of negligence and, in extreme cases, the
charge of
criminal negligence.
An engineer's work must also comply with numerous other rules and
regulations such as
building codes
and legislation pertaining to
environmental law.
Professional bodies of note for electrical engineers include the
Institute of
Electrical and Electronics Engineers (IEEE) and the
Institution of
Engineering and Technology (IET). The IEEE claims to produce
30% of the world's literature in electrical engineering, has over
360,000 members worldwide and holds over 3,000 conferences
annually. The IET publishes 21 journals, has a worldwide membership
of over 150,000, and claims to be the largest professional
engineering society in Europe. Obsolescence of technical skills is
a serious concern for electrical engineers. Membership and
participation in technical societies, regular reviews of
periodicals in the field and a habit of continued learning are
therefore essential to maintaining proficiency.
In Australia, Canada and the United States electrical engineers
make up around 0.25% of the labor force (see
note).
Outside of Europe and North America, engineering graduates
per-capita, and hence probably electrical engineering graduates
also, are most numerous in Taiwan, Japan, and South Korea.
Tools and work
From the
Global Positioning
System to
electric power
generation, electrical engineers have contributed to the
development of a wide range of technologies. They design, develop,
test and supervise the deployment of electrical systems and
electronic devices. For example, they may work on the design of
telecommunication systems, the
operation of
electric power stations,
the
lighting and
wiring of
buildings, the design of
household appliances or the electrical
control of industrial machinery.
Fundamental to the discipline are the sciences of
physics and
mathematics
as these help to obtain both a
qualitative and
quantitative description of how such systems will
work. Today most
engineering work
involves the use of
computers and it is
commonplace to use
computer-aided
design programs when designing electrical systems.
Nevertheless, the ability to sketch ideas is still invaluable for
quickly communicating with others.
Although most electrical engineers will understand basic
circuit theory (that is the interactions of
elements such as
resistors,
capacitors,
diodes,
transistors and
inductors in a circuit), the theories employed by
engineers generally depend upon the work they do. For example,
quantum mechanics and
solid state physics might be relevant to
an engineer working on
VLSI (the design of
integrated circuits), but are largely irrelevant to engineers
working with macroscopic electrical systems. Even
circuit theory may not be relevant to a
person designing telecommunication systems that use
off-the-shelf components. Perhaps
the most important technical skills for electrical engineers are
reflected in university programs, which emphasize
strong numerical skills,
computer literacy and the ability to
understand the
technical language
and concepts that relate to electrical engineering.
For many engineers, technical work accounts for only a fraction of
the work they do. A lot of time may also be spent on tasks such as
discussing proposals with clients, preparing
budgets and determining
project schedules. Many senior
engineers manage a team of
technicians or
other engineers and for this reason
project management skills are important.
Most engineering projects involve some form of documentation and
strong written communication
skills are therefore very important.
The
workplaces of electrical engineers are
just as varied as the types of work they do. Electrical engineers
may be found in the pristine lab environment of a
fabrication plant, the offices of a
consulting firm or on site at a
mine. During their working life, electrical
engineers may find themselves supervising a wide range of
individuals including
scientists,
electricians,
computer programmers and other
engineers.
Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular
of which are listed below. Although there are electrical engineers
who focus exclusively on one of these sub-disciplines, many deal
with a combination of them. Sometimes certain fields, such as
electronic engineering and computer engineering, are considered
separate disciplines in their own right.
Power
Power pole
Power engineering deals with the
generation,
transmission and
distribution of
electricity as well as the design of a range of
related devices. These include
transformers,
electric generators,
electric motors, high voltage engineering and
power electronics. In many regions
of the world, governments maintain an electrical network called a
power grid that connects a variety of
generators together with users of their energy. Users purchase
electrical energy from the grid, avoiding the costly exercise of
having to generate their own. Power engineers may work on the
design and maintenance of the power grid as well as the power
systems that connect to it. Such systems are called
on-grid power systems and may supply the grid with
additional power, draw power from the grid or do both. Power
engineers may also work on systems that do not connect to the grid,
called
off-grid power systems, which in some cases are
preferable to on-grid systems. The future includes Satellite
controlled power systems, with feedback in real time to prevent
power surges and prevent blackouts.
Control
Control engineering focuses on
the
modeling of a diverse range
of
dynamic systems and the design of
controllers that will
cause these systems to behave in the desired manner. To implement
such controllers electrical engineers may use
electrical circuits,
digital signal processors,
microcontrollers and
PLCs (Programmable Logic
Controllers).
Control
engineering has a wide range of applications from the flight
and propulsion systems of
commercial
airliners to the
cruise control
present in many modern
automobiles. It
also plays an important role in
industrial automation.
Control engineers often utilize
feedback
when designing
control systems. For
example, in an
automobile with
cruise control the vehicle's
speed is continuously monitored and fed back to the
system which adjusts the
motor's power output
accordingly. Where there is regular feedback,
control theory can be used to determine how
the system responds to such feedback.
Electronics
Electronic engineering
involves the design and testing of
electronic circuits that use the
properties of
components such as
resistors,
capacitors,
inductors,
diodes and
transistors to achieve a particular
functionality. The
tuned circuit,
which allows the user of a
radio to
filter out all but a single station, is
just one example of such a circuit. Another example (of a pneumatic
signal conditioner) is shown in the adjacent photograph.
Prior to the second world war, the subject was commonly known as
radio engineering and basically was restricted to aspects
of communications and
radar,
commercial radio and
early
television. Later, in post war years, as consumer devices began
to be developed, the field grew to include modern television, audio
systems,
computers and
microprocessors. In the mid to late 1950s,
the term
radio engineering gradually gave way to the name
electronic engineering.
Before the invention of the
integrated circuit in 1959, electronic
circuits were constructed from discrete components that could be
manipulated by humans. These discrete circuits consumed much space
and
power and were limited in speed,
although they are still common in some applications. By contrast,
integrated circuits packed a
large number—often millions—of tiny electrical components, mainly
transistors, into a small chip around the
size of a
coin. This allowed for the powerful
computers and other electronic devices we
see today.
Microelectronics
Microelectronics engineering deals
with the design and
microfabrication of very small electronic
circuit components for use in an
integrated circuit or sometimes for use
on their own as a general electronic component. The most common
microelectronic components are
semiconductor transistors, although all main electronic
components (
resistors,
capacitors,
inductors)
can be created at a microscopic level.
Nanoelectronics is the further
scaling of devices down to
nanometer levels.
Microelectronic components are created by chemically fabricating
wafers of semiconductors such as silicon (at higher frequencies,
compound semiconductors like
gallium arsenide and indium phosphide) to obtain the desired
transport of electronic charge and control of current. The field of
microelectronics involves a significant amount of chemistry and
material science and requires the electronic engineer working in
the field to have a very good working knowledge of the effects of
quantum mechanics.
Signal processing
Signal processing deals with the
analysis and manipulation of
signals. Signals can be either
analog, in which case the signal
varies continuously according to the information, or
digital, in which case the signal varies
according to a series of discrete values representing the
information. For analog signals, signal processing may involve the
amplification and
filtering of audio signals for
audio equipment or the
modulation and
demodulation of signals for
telecommunications. For digital signals,
signal processing may involve the
compression,
error detection and
error correction of digitally sampled
signals.
Signal Processing is a very mathematically oriented and intensive
area forming the core of
digital signal processing and it
is rapidly expanding with new applications in every field of
electrical engineering such as communications, control, radar,
TV/Audio/Video engineering, power electronics and bio-medical
engineering as many already existing analog systems are replaced
with their digital counterparts.
Although in the classical era,
analog signal processing only
provided a mathematical description of a system to be designed,
which is actually implemented by the
analog hardware engineers, Digital Signal
Processing both provides a mathematical description of the systems
to be designed and also actually implements them (either by
software programming or by hardware embedding) without much
dependency on hardware issues, which exponentiates the importance
and success of DSP engineering.
The deep and strong relations between signals and the information
they carry makes signal processing equivalent of information
processing. Which is the reason why the field finds so many
diversified applications. DSP processor ICs are found in every type
of modern electronic systems and products including,
SDTV |
HDTV sets, radios and mobile
communication devices,
Hi-Fi audio equipments,
Dolby noise
reduction algorithms,
GSM mobile phones,
mp3 multimedia players, camcorders and digital
cameras, automobile control systems,
noise cancelling headphones, digital
spectrum analyzers, intelligent
missile guidance,
radar,
GPS based cruise control systems and all kinds of
image processing,
video processing,
audio processing and
speech processing systems.
Telecommunications
Telecommunications engineering
focuses on the
transmission of
information across a
channel such as a
coax cable,
optical
fiber or
free space. Transmissions
across free space require information to be encoded in a
carrier wave in order to shift the information
to a
carrier frequency suitable
for transmission, this is known as
modulation. Popular analog modulation techniques
include
amplitude modulation
and
frequency modulation. The
choice of modulation affects the cost and performance of a system
and these two factors must be balanced carefully by the
engineer.
Once the transmission characteristics of a system are determined,
telecommunication engineers design the
transmitters and
receivers needed for such systems. These
two are sometimes combined to form a two-way communication device
known as a
transceiver. A key
consideration in the design of transmitters is their
power consumption as this is closely
related to their
signal strength. If
the signal strength of a transmitter is insufficient the signal's
information will be corrupted by
noise.
Instrumentation
Instrumentation
engineering deals with the design of devices to measure
physical quantities such as
pressure,
flow and
temperature. The design of such instrumentation
requires a good understanding of
physics
that often extends beyond
electromagnetic theory. For example,
radar guns use the
Doppler effect to measure the speed of
oncoming vehicles. Similarly,
thermocouples use the
Peltier-Seebeck effect to measure the
temperature difference between two points.
Often instrumentation is not used by itself, but instead as the
sensors of larger electrical systems. For
example, a thermocouple might be used to help ensure a furnace's
temperature remains constant. For this reason, instrumentation
engineering is often viewed as the counterpart of control
engineering.
Computers
Computer engineering deals with
the design of
computers and
computer systems. This may involve the
design of new
hardware, the design of
PDAs or the use of
computers to control an
industrial
plant. Computer engineers may also work on a system's
software. However, the design of complex software
systems is often the domain of
software engineering, which is usually
considered a separate discipline.
Desktop computers represent a tiny fraction
of the devices a computer engineer might work on, as computer-like
architectures are now found in a range of devices including
video game consoles and
DVD players.
Related disciplines
Mechatronics is an engineering
discipline which deals with the convergence of electrical and
mechanical systems. Such combined systems
are known as
electromechanical
systems and have widespread adoption. Examples include
automated manufacturing systems,
heating, ventilation and air-conditioning systems and
various subsystems of
aircraft and
automobiles.
The term
mechatronics is typically used to refer to
macroscopic systems but
futurists have predicted the emergence of
very small electromechanical devices. Already such small devices,
known as
micro electromechanical systems
(MEMS), are used in automobiles to tell
airbags when to deploy, in
digital projectors to create sharper
images and in
inkjet printers to
create nozzles for high definition printing. In the future it is
hoped the devices will help build tiny implantable medical devices
and improve
optical
communication.
Biomedical engineering is
another related discipline, concerned with the design of
medical equipment. This includes fixed
equipment such as
ventilators,
MRI scanners and
electrocardiograph monitors as well as
mobile equipment such as
cochlear
implants,
artificial
pacemakers and
artificial
hearts.
See also
Note
Note
I - There were around 300,000 people ( ) working as
electrical engineers in the US; in Australia, there were around
17,000 ( ) and in Canada, there were around 37,000 ( ),
constituting about 0.2% of the labour force in each of the three
countries. Australia and Canada reported that 96% and 88% of their
electrical engineers respectively are male.
References
- Vaunt Design Group. (2005). Inventor Alessandro Volta Biography. Troy MI:
The Great Idea Finder. Accessed 21 March 2008.
- (published 1996 in the NFPA Journal)
- Leland Anderson, "Nikola Tesla On His Work With Alternating
Currents and Their Application to Wireless Telegraphy, Telephony,
and Transmission of Power", Sun Publishing Company, LC
92-60482, ISBN 0-9632652-0-2 (ed. excerpts available online)
- Marconi's biography at Nobelprize.org retrieved
21 June 2008.
- Various including graduate degree requirements at
MIT, study guide at UWA, the curriculum at Queen's and unit tables at Aberdeen
- (see here regarding
copyright)
- (see Internet Archive)
- Trevelyan, James; (2005). What Do Engineers Really
Do?. University of Western Australia. (seminar with slides)
- See also: and and
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