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Electrical engineering

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   … and complex electronic circuits.
   Enlarge
   … and complex electronic circuits.

   Electrical engineering (sometimes referred to as electrical and
   electronic engineering) is a professional engineering discipline that
   deals with the study and application of electricity, electronics and
   electromagnetism. The field first became an identifiable occupation in
   the late nineteenth century with the commercialization of the electric
   telegraph and electrical power supply. The field now covers a range of
   sub-disciplines including those that deal with power, optoelectronics,
   digital electronics, analog electronics, computer science, artificial
   intelligence, control systems, electronics, signal processing and
   telecommunications.

   The term electrical engineering may or may not encompass electronic
   engineering. Where a distinction is made, 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. Another
   way of looking at the distinction is that electrical engineers are
   usually concerned with using electricity to transmit energy, while
   electronics engineers are concerned with using electricity to transmit
   information.

History

Early developments

   Electricity has been a subject of scientific interest since at least
   the 17th century, but 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 on 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 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.
   Thomas Edison built the world's first large-scale electrical supply
   network
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   Thomas Edison built the world's first large-scale electrical supply
   network

   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 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.
   Nikola Tesla made long-distance electrical transmission networks
   possible.
   Enlarge
   Nikola Tesla made long-distance electrical transmission networks
   possible.

   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

   Emergence of radio and electronics

   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). 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 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 towards 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. In 1968 Marcian Hoff
   invented the first microprocessor at Intel and thus ignited the
   development of the personal computer. The first realization of the
   microprocessor was the Intel 4004, a 4-bit processor developed in 1971,
   but only in 1973 did the Intel 8080, an 8-bit processor, make the
   building of 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, a Master of
   Engineering Management, a Doctor of Philosophy in Engineering 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 consists of a significant research component and is 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 the United Kingdom, Ireland, India 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, such as Australia, 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 Electrical Engineers (IEE). The IEEE claims to produce
   30 percent of the world's literature in electrical engineering, has
   over 360,000 members worldwide and holds over 300 conferences annually.
   The IEE publishes 14 journals, has a worldwide membership of 120,000,
   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 countries such as Australia, Canada and the United States electrical
   engineers make up around 0.25% of the labour force (see note). Outside
   of these countries, it is difficult to gauge the demographics of the
   profession due to less meticulous reporting on labour statistics.
   However, in terms of electrical engineering graduates per-capita,
   electrical engineering graduates would probably be most numerous in
   countries such as Taiwan, Japan and South Korea.

Tools and work

   From the Global Positioning System to electric power generation,
   electrical engineers are responsible for 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.
   Satellite Communications is one of many projects an electrical engineer
   might work on
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   Satellite Communications is one of many projects an electrical engineer
   might work on

   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 most engineers technical work accounts for only a fraction of the
   work they do. A lot of time is also 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 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 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.

Control

   Control engineering focuses on the modelling 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 and microcontrollers. 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 speed 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 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.

   Microelectronic components are created by chemically fabricating wafers
   of semiconductors such as silicon (at higher frequencies, 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 manipulations 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.

Telecommunications

   Telecommunications engineering focuses on the transmission of
   information across a channel such as a coax cable, optical fibre 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 engineering

   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.

   Retrieved from " http://en.wikipedia.org/wiki/Electrical_engineering"
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