Electrical engineering

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Electrical engineering
Occupation
NamesElectrical engineer
Activity sectors
Electronics, electrical circuits, electromagnetics, power engineering, electrical machines, telecommunication, control systems, signal processing, optics, photonics and electrical substations
Specialty{{#statements:P1995}}
Description
CompetenciesTechnical knowledge, management skills, advanced mathematics, systems design, physics, abstract thinking, analytical thinking, philosophy of logic (see also Glossary of electrical and electronics engineering)
Fields of
employment
Technology, science, exploration, military, industry and society

Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the latter half of the 19th century after the commercialization of the electric telegraph, the telephone, and electrical power generation, distribution, and use.

Electrical engineering is now divided into a wide range of different fields, including computer engineering, systems engineering, power engineering, telecommunications, radio-frequency engineering, signal processing, instrumentation, photovoltaic cells, electronics, and optics and photonics. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering, power electronics, electromagnetics and waves, microwave engineering, nanotechnology, electrochemistry, renewable energies, mechatronics/control, and electrical materials science.<ref group="lower-alpha">For more see glossary of electrical and electronics engineering.</ref>

Electrical engineers typically hold a degree in electrical engineering or electronic engineering. Practicing engineers may have professional certification and be members of a professional body or an international standards organization. These include the International Electrotechnical Commission (IEC), the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET, formerly the IEE).

Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from circuit theory to the management skills of a project manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter to sophisticated design and manufacturing software.

History

Main article: History of electrical engineering

Electricity has been a subject of scientific interest since at least the early 17th century. William Gilbert was a prominent early electrical scientist, and was the first to draw a clear distinction between magnetism and static electricity. He is credited with establishing the term "electricity".<ref name="FOOTNOTEMartinsenGrimnes2011411">Martinsen & Grimnes 2011, p. 411.</ref> He also designed the versorium: a device that detects the presence of statically charged objects. In 1762 Swedish professor Johan Wilcke invented a device later named electrophorus that produced a static electric charge. By 1800 Alessandro Volta had developed the voltaic pile, a forerunner of the electric battery.<ref>"The Voltaic Pile | Distinctive Collections Spotlights". libraries.mit.edu. Retrieved 16 December 2022.</ref>

19th century

The discoveries of Michael Faraday formed the foundation of electric motor technology.

In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of Hans Christian Ørsted, who discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle; of William Sturgeon, who in 1825 invented the electromagnet; of Joseph Henry and Edward Davy, who invented the electrical relay in 1835; of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor; of Michael Faraday, the discoverer of electromagnetic induction in 1831; and of James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.<ref name="FOOTNOTELambourne201011">Lambourne 2010, p. 11.</ref>

In 1782, Georges-Louis Le Sage developed and presented in Berlin probably the world's first form of electric telegraphy, using 24 different wires, one for each letter of the alphabet. This telegraph connected two rooms. It was an electrostatic telegraph that moved gold leaf through electrical conduction.

In 1795, Francisco Salva Campillo proposed an electrostatic telegraph system. Between 1803 and 1804, he worked on electrical telegraphy, and in 1804, he presented his report at the Royal Academy of Natural Sciences and Arts of Barcelona. Salva's electrolyte telegraph system was very innovative though it was greatly influenced by and based upon two discoveries made in Europe in 1800—Alessandro Volta's electric battery for generating an electric current and William Nicholson and Anthony Carlyle's electrolysis of water.<ref>"Francesc Salvà i Campillo : Biography". ethw.org. 25 January 2016. Retrieved 25 March 2019.</ref> Electrical telegraphy may be considered the first example of electrical engineering.<ref>Roberts, Steven. "Distant Writing: A History of the Telegraph Companies in Britain between 1838 and 1868: 2. Introduction". Using these discoveries a number of inventors or rather 'adapters' appeared, taking this new knowledge, transforming it into useful ideas with commercial utility; the first of these 'products' was the use of electricity to transmit information between distant points, the electric telegraph.</ref> Electrical engineering became a profession in the later 19th century. Practitioners had created a global electric telegraph network, and the first professional electrical engineering institutions were founded in the UK and the US to support the new discipline. Francis Ronalds created an electric telegraph system in 1816 and documented his vision of how the world could be transformed by electricity.<ref>Ronalds, B.F. (2016). Sir Francis Ronalds: Father of the Electric Telegraph. London: Imperial College Press. ISBN 978-1-78326-917-4.</ref><ref>Ronalds, B.F. (2016). "Sir Francis Ronalds and the Electric Telegraph". International Journal for the History of Engineering & Technology. 86: 42–55. doi:10.1080/17581206.2015.1119481. S2CID 113256632.</ref> Over 50 years later, he joined the new Society of Telegraph Engineers (soon to be renamed the Institution of Electrical Engineers) where he was regarded by other members as the first of their cohort.<ref>Ronalds, B.F. (July 2016). "Francis Ronalds (1788–1873): The First Electrical Engineer?". Proceedings of the IEEE. 104 (7): 1489–1498. doi:10.1109/JPROC.2016.2571358. S2CID 20662894.</ref> By the end of the 19th century, the world had been forever changed by the rapid communication made possible by the engineering development of land-lines, submarine cables, and, from about 1890, wireless telegraphy.

Practical applications and advances in such fields created an increasing need for standardized units of measure. They led to the international standardization of the units volt, ampere, coulomb, ohm, farad, and henry. This was achieved at an international conference in Chicago in 1893.<ref name="FOOTNOTERosenberg20089">Rosenberg 2008, p. 9.</ref> The publication of these standards formed the basis of future advances in standardization in various industries, and in many countries, the definitions were immediately recognized in relevant legislation.<ref name="FOOTNOTETunbridge1992">Tunbridge 1992.</ref>

During these years, the study of electricity was largely considered to be a subfield of physics since early electrical technology was considered electromechanical in nature. The Technische Universität Darmstadt founded the world's first department of electrical engineering in 1882 and introduced the first-degree course in electrical engineering in 1883.<ref>Darmstadt, Technische Universität. "Historie". Technische Universität Darmstadt. Retrieved 12 October 2019.</ref> The first electrical engineering degree program in the United States was started at Massachusetts Institute of Technology (MIT) in the physics department under Professor Charles Cross, <ref name="FOOTNOTEWildesLindgren198519">Wildes & Lindgren 1985, p. 19.</ref> though it was Cornell University to produce the world's first electrical engineering graduates in 1885.<ref>"History". School of Electrical and Computer Engineering, Cornell. Spring 1994 [Later updated]. Archived from the original on 6 June 2013.</ref> The first course in electrical engineering was taught in 1883 in Cornell's Sibley College of Mechanical Engineering and Mechanic Arts.<ref>Roger Segelken, H. (2009). A tradition of leadership and innovation: a history of Cornell Engineering (PDF). Ithaca, NY. ISBN 978-0-918531-05-6. OCLC 455196772. Archived from the original (PDF) on 3 March 2016.{{cite book}}: CS1 maint: location missing publisher (link)</ref>

In about 1885, Cornell President Andrew Dickson White established the first Department of Electrical Engineering in the United States.<ref>"Andrew Dickson White | Office of the President". president.cornell.edu.</ref> In the same year, University College London founded the first chair of electrical engineering in Great Britain.<ref>The Electrical Engineer. 1911. p. 54.</ref> Professor Mendell P. Weinbach at University of Missouri established the electrical engineering department in 1886.<ref>"Department History – Electrical & Computer Engineering". Archived from the original on 17 November 2015. Retrieved 5 November 2015.</ref> Afterwards, universities and institutes of technology gradually started to offer electrical engineering programs to their students all over the world.

During these decades the use of electrical engineering increased dramatically. In 1882, Thomas Edison switched on the world's first large-scale electric power network that provided 110 volts—direct current (DC)—to 59 customers on Manhattan Island in New York City. In 1884, Sir Charles Parsons invented the steam turbine allowing for more efficient electric power generation. Alternating current, with its ability to transmit power more efficiently over long distances via the use of transformers, developed rapidly in the 1880s and 1890s with transformer designs by Károly Zipernowsky, Ottó Bláthy and Miksa Déri (later called ZBD transformers), Lucien Gaulard, John Dixon Gibbs and William Stanley, Jr. Practical AC motor designs including induction motors were independently invented by Galileo Ferraris and Nikola Tesla and further developed into a practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown.<ref name="FOOTNOTEHeertjePerlman1990138">Heertje & Perlman 1990, p. 138.</ref> Charles Steinmetz and Oliver Heaviside contributed to the theoretical basis of alternating current engineering.<ref>Grattan-Guinness, I. (1 January 2003). Companion Encyclopedia of the History and Philosophy of the Mathematical Sciences. JHU Press. ISBN 9780801873973 – via Google Books.</ref><ref>Suzuki, Jeff (27 August 2009). Mathematics in Historical Context. MAA. ISBN 9780883855706 – via Google Books.</ref> The spread in the use of AC set off in the United States what has been called the war of the currents between a George Westinghouse backed AC system and a Thomas Edison backed DC power system, with AC being adopted as the overall standard.<ref name="FOOTNOTESeversLeise2011145">Severs & Leise 2011, p. 145.</ref>

Early 20th century

Guglielmo Marconi, known for his pioneering work on long-distance radio transmission

During the development of radio, many scientists and inventors contributed to radio technology and electronics. The mathematical work of James Clerk Maxwell during the 1850s had shown the relationship of different forms of electromagnetic radiation including the possibility of invisible airborne waves (later called "radio waves"). In his classic physics experiments of 1888, Heinrich Hertz proved Maxwell's theory by transmitting radio waves with a spark-gap transmitter, and detected them by using simple electrical devices. Other physicists experimented with these new waves and in the process developed devices for transmitting and detecting them. In 1895, Guglielmo Marconi began work on a way to adapt the known methods of transmitting and detecting these "Hertzian waves" into a purpose built commercial wireless telegraphic system. 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 2,100 miles (3,400 km).<ref>Marconi's biography at Nobelprize.org retrieved 21 June 2008.</ref>

Millimetre wave communication was first investigated by Jagadish Chandra Bose during 1894–1896, when he reached an extremely high frequency of up to 60 GHz in his experiments.<ref>"Milestones: First Millimeter-wave Communication Experiments by J.C. Bose, 1894–96". List of IEEE milestones. Institute of Electrical and Electronics Engineers. Retrieved 1 October 2019.</ref> He also introduced the use of semiconductor junctions to detect radio waves,<ref name=emerson>Emerson, D. T. (1997). "The work of Jagadis Chandra Bose: 100 years of mm-wave research". 1997 IEEE MTT-S International Microwave Symposium Digest. Vol. 45. IEEE Transactions on Microwave Theory and Research. pp. 2267–2273. Bibcode:1997imsd.conf..553E. CiteSeerX 10.1.1.39.8748. doi:10.1109/MWSYM.1997.602853. ISBN 9780986488511. S2CID 9039614. reprinted in Igor Grigorov, Ed., Antentop, Vol. 2, No.3, pp. 87–96.</ref> when he patented the radio crystal detector in 1901.<ref name="computerhistory-timeline">"Timeline". The Silicon Engine. Computer History Museum. Retrieved 22 August 2019.</ref><ref name="computerhistory-1901">"1901: Semiconductor Rectifiers Patented as "Cat's Whisker" Detectors". The Silicon Engine. Computer History Museum. Retrieved 23 August 2019.</ref>

In 1897, Karl Ferdinand Braun introduced the cathode-ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.<ref name="FOOTNOTEAbramson195522">Abramson 1955, p. 22.</ref> 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.<ref name="FOOTNOTEHuurdeman2003226">Huurdeman 2003, p. 226.</ref>

In 1920, Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.<ref>"Albert W. Hull (1880–1966)". IEEE History Center. Archived from the original on 2 June 2002. Retrieved 22 January 2006.</ref><ref>"Who Invented Microwaves?". Retrieved 22 January 2006.</ref> 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.<ref>"Early Radar History". Peneley Radar Archives. Retrieved 22 January 2006.</ref>

In 1941, Konrad Zuse presented the Z3, the world's first fully functional and programmable computer using electromechanical parts. In 1943, Tommy Flowers designed and built the Colossus, the world's first fully functional, electronic, digital and programmable computer.<ref>Rojas, Raúl (2002). "The history of Konrad Zuse's early computing machines". In Rojas, Raúl; Hashagen, Ulf (eds.). The First Computers—History and Architectures History of Computing. MIT Press. p. 237. ISBN 978-0-262-68137-7.</ref><ref>Sale, Anthony E. (2002). "The Colossus of Bletchley Park". In Rojas, Raúl; Hashagen, Ulf (eds.). The First Computers—History and Architectures History of Computing. MIT Press. pp. 354–355. ISBN 978-0-262-68137-7.</ref> 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.<ref>"The ENIAC Museum Online". Retrieved 18 January 2006.</ref>

In 1948, Claude Shannon published "A Mathematical Theory of Communication" which mathematically describes the passage of information with uncertainty (electrical noise).

Solid-state electronics

See also: History of electronic engineering, History of the transistor, Invention of the integrated circuit, MOSFET, and Solid-state electronics
A replica of the first working transistor, a point-contact transistor
Metal–oxide–semiconductor field-effect transistor (MOSFET), the basic building block of modern electronics

The first working transistor was a point-contact transistor invented by John Bardeen and Walter Houser Brattain while working under William Shockley at the Bell Telephone Laboratories (BTL) in 1947.<ref>"1947: Invention of the Point-Contact Transistor". Computer History Museum. Retrieved 10 August 2019.</ref> They then invented the bipolar junction transistor in 1948.<ref>"1948: Conception of the Junction Transistor". The Silicon Engine. Computer History Museum. Retrieved 8 October 2019.</ref> While early junction transistors were relatively bulky devices that were difficult to manufacture on a mass-production basis,<ref name="Moskowitz">Moskowitz, Sanford L. (2016). Advanced Materials Innovation: Managing Global Technology in the 21st century. John Wiley & Sons. p. 168. ISBN 9780470508923.</ref> they opened the door for more compact devices.<ref>"Electronics Timeline". Greatest Engineering Achievements of the Twentieth Century. Retrieved 18 January 2006.</ref>

The first integrated circuits were the hybrid integrated circuit invented by Jack Kilby at Texas Instruments in 1958 and the monolithic integrated circuit chip invented by Robert Noyce at Fairchild Semiconductor in 1959.<ref name="Saxena140">Saxena, Arjun N. (2009). Invention of Integrated Circuits: Untold Important Facts. World Scientific. p. 140. ISBN 9789812814456.</ref>

The MOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) was invented by Mohamed Atalla and Dawon Kahng at BTL in 1959.<ref name="computerhistory">"1960 – Metal Oxide Semiconductor (MOS) Transistor Demonstrated". The Silicon Engine. Computer History Museum.</ref><ref name="computerhistory-transistor">"Who Invented the Transistor?". Computer History Museum. 4 December 2013. Retrieved 20 July 2019.</ref><ref name="triumph">"Triumph of the MOS Transistor". YouTube. Computer History Museum. 6 August 2010. Archived from the original on 28 October 2021. Retrieved 21 July 2019.</ref> It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses.<ref name="Moskowitz"/> It revolutionized the electronics industry,<ref name="Chan">Chan, Yi-Jen (1992). Studies of InAIAs/InGaAs and GaInP/GaAs heterostructure FET's for high speed applications. University of Michigan. p. 1. The Si MOSFET has revolutionized the electronics industry and as a result impacts our daily lives in almost every conceivable way.</ref><ref name="Grant">Grant, Duncan Andrew; Gowar, John (1989). Power MOSFETS: theory and applications. Wiley. p. 1. ISBN 9780471828679. The metal–oxide–semiconductor field-effect transistor (MOSFET) is the most commonly used active device in the very large-scale integration of digital integrated circuits (VLSI). During the 1970s these components revolutionized electronic signal processing, control systems and computers.</ref> becoming the most widely used electronic device in the world.<ref name="computerhistory-transistor"/><ref name="Golio">Golio, Mike; Golio, Janet (2018). RF and Microwave Passive and Active Technologies. CRC Press. pp. 18–2. ISBN 9781420006728.</ref><ref name="computerhistory2018">"13 Sextillion & Counting: The Long & Winding Road to the Most Frequently Manufactured Human Artifact in History". Computer History Museum. 2 April 2018. Retrieved 28 July 2019.</ref>

The MOSFET made it possible to build high-density integrated circuit chips.<ref name="computerhistory-transistor"/> The earliest experimental MOS IC chip to be fabricated was built by Fred Heiman and Steven Hofstein at RCA Laboratories in 1962.<ref name="computerhistory-digital">"Tortoise of Transistors Wins the Race – CHM Revolution". Computer History Museum. Retrieved 22 July 2019.</ref> MOS technology enabled Moore's law, the doubling of transistors on an IC chip every two years, predicted by Gordon Moore in 1965.<ref>Franco, Jacopo; Kaczer, Ben; Groeseneken, Guido (2013). Reliability of High Mobility SiGe Channel MOSFETs for Future CMOS Applications. Springer Science & Business Media. pp. 1–2. ISBN 9789400776630.</ref> Silicon-gate MOS technology was developed by Federico Faggin at Fairchild in 1968.<ref>"1968: Silicon Gate Technology Developed for ICs". Computer History Museum. Retrieved 22 July 2019.</ref> Since then, the MOSFET has been the basic building block of modern electronics.<ref name="triumph"/><ref>McCluskey, Matthew D.; Haller, Eugene E. (2012). Dopants and Defects in Semiconductors. CRC Press. p. 3. ISBN 9781439831533.</ref><ref name="nytimes.com">Daniels, Lee A. (28 May 1992). "Dr. Dawon Kahng, 61, Inventor in Field of Solid-State Electronics". The New York Times. Retrieved 1 April 2017.</ref> The mass-production of silicon MOSFETs and MOS integrated circuit chips, along with continuous MOSFET scaling miniaturization at an exponential pace (as predicted by Moore's law), has since led to revolutionary changes in technology, economy, culture and thinking.<ref name="Feldman">Feldman, Leonard C. (2001). "Introduction". Fundamental Aspects of Silicon Oxidation. Springer Science & Business Media. pp. 1–11. ISBN 9783540416821.</ref>

The Apollo program which culminated in landing astronauts on the Moon with Apollo 11 in 1969 was enabled by NASA's adoption of advances in semiconductor electronic technology, including MOSFETs in the Interplanetary Monitoring Platform (IMP)<ref>Butler, P. M. (29 August 1989). Interplanetary Monitoring Platform (PDF). NASA. pp. 1, 11, 134. Retrieved 12 August 2019.</ref><ref>White, H. D.; Lokerson, D. C. (1971). "The Evolution of IMP Spacecraft Mosfet Data Systems". IEEE Transactions on Nuclear Science. 18 (1): 233–236. Bibcode:1971ITNS...18..233W. doi:10.1109/TNS.1971.4325871. ISSN 0018-9499.</ref> and silicon integrated circuit chips in the Apollo Guidance Computer (AGC).<ref>"Apollo Guidance Computer and the First Silicon Chips". National Air and Space Museum. Smithsonian Institution. 14 October 2015. Retrieved 1 September 2019.</ref>

The development of MOS integrated circuit technology in the 1960s led to the invention of the microprocessor in the early 1970s.<ref name="computerhistory1971">"1971: Microprocessor Integrates CPU Function onto a Single Chip". Computer History Museum. Retrieved 22 July 2019.</ref><ref name="Colinge2016">Colinge, Jean-Pierre; Greer, James C. (2016). Nanowire Transistors: Physics of Devices and Materials in One Dimension. Cambridge University Press. p. 2. ISBN 9781107052406.</ref> The first single-chip microprocessor was the Intel 4004, released in 1971.<ref name="computerhistory1971"/> The Intel 4004 was designed and realized by Federico Faggin at Intel with his silicon-gate MOS technology,<ref name="computerhistory1971"/> along with Intel's Marcian Hoff and Stanley Mazor and Busicom's Masatoshi Shima.<ref name="ieee">Faggin, Federico (2009). "The Making of the First Microprocessor". IEEE Solid-State Circuits Magazine. 1: 8–21. doi:10.1109/MSSC.2008.930938. S2CID 46218043.</ref> The microprocessor led to the development of microcomputers and personal computers, and the microcomputer revolution.

Subfields

One of the properties of electricity is that it is very useful for energy transmission as well as for information transmission. These were also the first areas in which electrical engineering was developed. Today, electrical engineering has many subdisciplines, the most common of which are listed below. Although there are electrical engineers who focus exclusively on one of these subdisciplines, many deal with a combination of them. Sometimes, certain fields, such as electronic engineering and computer engineering, are considered disciplines in their own right.

Power and energy

Main articles: Power engineering and Energy engineering
The top of a power pole

Power & Energy engineering deals with the generation, transmission, and distribution of electricity as well as the design of a range of related devices.<ref name="FOOTNOTEGrigsby2012">Grigsby 2012.</ref> 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.<ref name="UNESCO"/> 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.

Telecommunications

Main article: Telecommunications engineering
Satellite dishes are a crucial component in the analysis of satellite information.

Telecommunications engineering focuses on the transmission of information across a communication channel such as a coax cable, optical fiber or free space.<ref name="FOOTNOTETobin200715">Tobin 2007, p. 15.</ref> Transmissions across free space require information to be encoded in a carrier signal 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.<ref name="FOOTNOTEChandrasekhar200621">Chandrasekhar 2006, p. 21.</ref> 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.<ref name="FOOTNOTESmith200719">Smith 2007, p. 19.</ref><ref name="FOOTNOTEZhangHuLuo2007448">Zhang, Hu & Luo 2007, p. 448.</ref> Typically, if the power of the transmitted signal is insufficient once the signal arrives at the receiver's antenna(s), the information contained in the signal will be corrupted by noise, specifically static.

Control engineering

Main articles: Control engineering and Control theory
Control systems play a critical role in spaceflight.

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.<ref name="FOOTNOTEBissell199617">Bissell 1996, p. 17.</ref> To implement such controllers, electronics control engineers may use electronic circuits, digital signal processors, microcontrollers, and programmable logic controllers (PLCs). 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.<ref name="FOOTNOTEMcDavidEchaore-McDavid200995">McDavid & Echaore-McDavid 2009, p. 95.</ref> It also plays an important role in industrial automation.

Control engineers often use 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.<ref name="FOOTNOTEÅströmMurray2021108">Åström & Murray 2021, p. 108.</ref> Where there is regular feedback, control theory can be used to determine how the system responds to such feedback.

Control engineers also work in robotics to design autonomous systems using control algorithms which interpret sensory feedback to control actuators that move robots such as autonomous vehicles, autonomous drones and others used in a variety of industries.<ref name="FOOTNOTEFairman1998119">Fairman 1998, p. 119.</ref>

Electronics

Main article: Electronic engineering
Electronic components

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.<ref name="UNESCO">Engineering: Issues, Challenges and Opportunities for Development. UNESCO. 2010. pp. 127–8. ISBN 978-92-3-104156-3.</ref> 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 to research is a pneumatic signal conditioner.

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.<ref name="UNESCO"/> 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,<ref name="FOOTNOTEThompson20064">Thompson 2006, p. 4.</ref> 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,<ref name="FOOTNOTEMerhari2009233">Merhari 2009, p. 233.</ref> into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.

Microelectronics and nanoelectronics

Main articles: Microelectronics, Nanoelectronics, and Chip design
Microprocessor

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.<ref name="FOOTNOTEBhushan1997581">Bhushan 1997, p. 581.</ref> The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors etc.) can be created at a microscopic level.

Nanoelectronics is the further scaling of devices down to nanometer levels. Modern devices are already in the nanometer regime, with below 100 nm processing having been standard since around 2002.<ref name="FOOTNOTEMook2008149">Mook 2008, p. 149.</ref>

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.<ref name="FOOTNOTESullivan2012">Sullivan 2012.</ref>

Signal processing

Main article: Signal processing
A Bayer filter on a CCD requires signal processing to get a red, green, and blue value at each pixel.

Signal processing deals with the analysis and manipulation of signals.<ref name="FOOTNOTETuzlukov201020">Tuzlukov 2010, p. 20.</ref> 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.<ref name="FOOTNOTEManolakisIngle201117">Manolakis & Ingle 2011, p. 17.</ref>

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, audio engineering, broadcast engineering, power electronics, and biomedical engineering as many already existing analog systems are replaced with their digital counterparts. Analog signal processing is still important in the design of many control systems.

DSP processor ICs are found in many types of modern electronic devices, such as digital television sets,<ref name="FOOTNOTEBayoumiSwartzlander199425">Bayoumi & Swartzlander 1994, p. 25.</ref> radios, hi-fi audio equipment, mobile phones, multimedia players, camcorders and digital cameras, automobile control systems, noise cancelling headphones, digital spectrum analyzers, missile guidance systems, radar systems, and telematics systems. In such products, DSP may be responsible for noise reduction, speech recognition or synthesis, encoding or decoding digital media, wirelessly transmitting or receiving data, triangulating positions using GPS, and other kinds of image processing, video processing, audio processing, and speech processing.<ref name="FOOTNOTEKhanna2009297">Khanna 2009, p. 297.</ref>

Instrumentation

Main article: Instrumentation engineering
Flight instruments provide pilots with the tools to control aircraft analytically.

Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure, flow, and temperature.<ref name="FOOTNOTEGrantBixley2011159">Grant & Bixley 2011, p. 159.</ref> The design of such instruments requires a good understanding of physics that often extends beyond electromagnetic theory. For example, flight instruments measure variables such as wind speed and altitude to enable pilots the control of aircraft analytically. Similarly, thermocouples use the Peltier-Seebeck effect to measure the temperature difference between two points.<ref name="FOOTNOTEFredlundRahardjoFredlund2012346">Fredlund, Rahardjo & Fredlund 2012, p. 346.</ref>

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.<ref>Manual on the Use of Thermocouples in Temperature Measurement. ASTM International. 1 January 1993. p. 154. ISBN 978-0-8031-1466-1.</ref> For this reason, instrumentation engineering is often viewed as the counterpart of control.

Computers

Main article: Computer engineering
Supercomputers are used in fields as diverse as computational biology and geographic information systems.

Computer engineering deals with the design of computers and computer systems. This may involve the design of new hardware. 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.<ref name="FOOTNOTEJalote200622">Jalote 2006, p. 22.</ref> 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 embedded devices including video game consoles and DVD players. Computer engineers are involved in many hardware and software aspects of computing.<ref>Lam, Herman; O'Malley, John R. (26 April 1988). Fundamentals of Computer Engineering: Logic Design and Microprocessors. Wiley. ISBN 0471605018.</ref> Robots are one of the applications of computer engineering.

Photonics and optics

Main articles: Photonics and Optics

Photonics and optics deals with the generation, transmission, amplification, modulation, detection, and analysis of electromagnetic radiation. The application of optics deals with design of optical instruments such as lenses, microscopes, telescopes, and other equipment that uses the properties of electromagnetic radiation. Other prominent applications of optics include electro-optical sensors and measurement systems, lasers, fiber-optic communication systems, and optical disc systems (e.g. CD and DVD). Photonics builds heavily on optical technology, supplemented with modern developments such as optoelectronics (mostly involving semiconductors), laser systems, optical amplifiers and novel materials (e.g. metamaterials).

Related disciplines

The Bird VIP Infant ventilator

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,<ref name="FOOTNOTEMahalik2003569">Mahalik 2003, p. 569.</ref> heating, ventilation and air-conditioning systems,<ref name="FOOTNOTELeondes2000199">Leondes 2000, p. 199.</ref> and various subsystems of aircraft and automobiles.<ref name="FOOTNOTEShettyKolk201036">Shetty & Kolk 2010, p. 36.</ref> Electronic systems design is the subject within electrical engineering that deals with the multi-disciplinary design issues of complex electrical and mechanical systems.<ref name="lienig">J. Lienig; H. Bruemmer (2017). Fundamentals of Electronic Systems Design. Springer International Publishing. p. 1. doi:10.1007/978-3-319-55840-0. ISBN 978-3-319-55839-4.</ref>

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 microelectromechanical systems (MEMS), are used in automobiles to tell airbags when to deploy,<ref name="FOOTNOTEMalufWilliams20043">Maluf & Williams 2004, p. 3.</ref> 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.<ref name="FOOTNOTEIgaKokubun2010137">Iga & Kokubun 2010, p. 137.</ref>

In aerospace engineering and robotics, an example is the most recent electric propulsion and ion propulsion.

Education

Main article: Education and training of electrical and electronics engineers
Oscilloscope

Electrical engineers typically possess an academic degree with a major in electrical engineering, electronics engineering, electrical engineering technology,<ref name=BLS3>"Electrical and Electronic Engineer". Occupational Outlook Handbook, 2012–13 Edition. Bureau of Labor Statistics, U.S. Department of Labor. Retrieved 15 November 2014.</ref> or electrical and electronic engineering.<ref name="FOOTNOTEChaturvedi1997253">Chaturvedi 1997, p. 253.</ref><ref>"What is the difference between electrical and electronic engineering?". FAQs – Studying Electrical Engineering. Retrieved 20 March 2012.</ref> The same fundamental principles are taught in all programs, though emphasis may vary according to title. 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 Science in Electrical/Electronics Engineering Technology, Bachelor of Engineering, Bachelor of Science, Bachelor of Technology, or Bachelor of Applied Science, depending on the university. The bachelor's degree generally includes units covering physics, mathematics, computer science, project management, and a variety of topics in electrical engineering.<ref name="Enterprise1986">Computerworld. IDG Enterprise. 25 August 1986. p. 97.</ref> Initially such topics cover most, if not all, of the subdisciplines of electrical engineering. At some schools, the students can then choose to emphasize one or more subdisciplines towards the end of their courses of study.

An example circuit diagram, which is useful in circuit design and troubleshooting

At many schools, electronic engineering is included as part of an electrical award, sometimes explicitly, such as a Bachelor of Engineering (Electrical and Electronic), but in others, electrical and electronic engineering are both considered to be sufficiently broad and complex that separate degrees are offered.<ref>"Electrical and Electronic Engineering". Archived from the original on 28 November 2011. Retrieved 8 December 2011.</ref>

Some electrical engineers choose to study for 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 (Eng.D.), or an Engineer's degree. The master's and engineer's degrees 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 some other European countries, Master of Engineering is often considered to be an undergraduate degree of slightly longer duration than the Bachelor of Engineering rather than a standalone postgraduate degree.<ref>Various including graduate degree requirements at MIT Archived 16 January 2006 at the Wayback Machine, study guide at UWA, the curriculum at Queen's Archived 4 August 2012 at the Wayback Machine and unit tables at Aberdeen Archived 22 August 2006 at the Wayback Machine</ref>

Professional practice

Belgian electrical engineers inspecting the rotor of a 40,000 kilowatt turbine of the General Electric Company in New York City

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.<ref name="Labor2008">Occupational Outlook Handbook, 2008–2009. U S Department of Labor, Jist Works. 1 March 2008. p. 148. ISBN 978-1-59357-513-7.</ref> 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 or Incorporated Engineer (in India, Pakistan, the United Kingdom, Ireland and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).

The IEEE corporate office is on the 17th floor of 3 Park Avenue in New York City.

The advantages of licensure 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".<ref>"Why Should You Get Licensed?". National Society of Professional Engineers. Archived from the original on 4 June 2005. Retrieved 11 July 2005.</ref> This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.<ref>"Engineers Act". Quebec Statutes and Regulations (CanLII). Retrieved 24 July 2005.</ref> 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.<ref>"Codes of Ethics and Conduct". Online Ethics Center. Archived from the original on 2 February 2016. Retrieved 24 July 2005.</ref> 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.<ref>"About the IEEE". IEEE. Retrieved 11 July 2005.</ref> The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.<ref>"About the IET". The IET. Retrieved 11 July 2005.</ref><ref>"Journal and Magazines". The IET. Archived from the original on 24 August 2007. Retrieved 11 July 2005.</ref> 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. An MIET(Member of the Institution of Engineering and Technology) is recognised in Europe as an Electrical and computer (technology) engineer.<ref>"Electrical and Electronics Engineers, except Computer". Occupational Outlook Handbook. Archived from the original on 13 July 2005. Retrieved 16 July 2005. (see here regarding copyright)</ref>

In Australia, Canada, and the United States, electrical engineers make up around 0.25% of the labor force.<ref group="lower-alpha">In May 2014 there were around 175,000 people working as electrical engineers in the US.<ref>"Electrical Engineers". www.bls.gov. Retrieved 30 November 2015.</ref> In 2012, Australia had around 19,000<ref>"Electrical Engineer Career Information for Migrants | Victoria, Australia". www.liveinvictoria.vic.gov.au. Archived from the original on 8 December 2015. Retrieved 30 November 2015.</ref> while in Canada, there were around 37,000 (as of 2007), 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.<ref>"Electrical Engineers". Bureau of Labor Statistics. Archived from the original on 19 February 2006. Retrieved 13 March 2009. See also: "Work Experience of the Population in 2006". Bureau of Labor Statistics. Retrieved 20 June 2008. and "Electrical and Electronics Engineers". Australian Careers. Archived from the original on 23 October 2009. Retrieved 13 March 2009. and "Electrical and Electronics Engineers". Canadian jobs service. Archived from the original on 6 March 2009. Retrieved 13 March 2009.</ref></ref>

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.<ref>"Electrical and Electronics Engineers, except Computer". Occupational Outlook Handbook. Archived from the original on 13 July 2005. Retrieved 16 July 2005. (see )</ref>

Satellite communications is typical of what electrical engineers 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.

The Shadow robot hand system

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.<ref name="FOOTNOTETaylor2008241">Taylor 2008, p. 241.</ref>

A laser bouncing down an acrylic rod, illustrating the total internal reflection of light in a multi-mode optical fiber

A wide range of instrumentation is used by electrical engineers. For simple control circuits and alarms, a basic multimeter measuring voltage, current, and resistance may suffice. Where time-varying signals need to be studied, the oscilloscope is also an ubiquitous instrument. In RF engineering and high frequency telecommunications, spectrum analyzers and network analyzers are used. In some disciplines, safety can be a particular concern with instrumentation. For instance, medical electronics designers must take into account that much lower voltages than normal can be dangerous when electrodes are directly in contact with internal body fluids.<ref name="FOOTNOTELeitgeb2010122">Leitgeb 2010, p. 122.</ref> Power transmission engineering also has great safety concerns due to the high voltages used; although voltmeters may in principle be similar to their low voltage equivalents, safety and calibration issues make them very different.<ref>Naidu & Kamaraju 2009, p. 210</ref> Many disciplines of electrical engineering use tests specific to their discipline. Audio electronics engineers use audio test sets consisting of a signal generator and a meter, principally to measure level but also other parameters such as harmonic distortion and noise. Likewise, information technology have their own test sets, often specific to a particular data format, and the same is true of television broadcasting.

Radome at the Misawa Air Base Misawa Security Operations Center, Misawa, Japan

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.<ref>Trevelyan, James (2005). "What Do Engineers Really Do?" (PDF). University of Western Australia.</ref> 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 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, on board a Naval ship, 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.<ref name="FOOTNOTEMcDavidEchaore-McDavid200987">McDavid & Echaore-McDavid 2009, p. 87.</ref>

Electrical engineering has an intimate relationship with the physical sciences. For instance, the physicist Lord Kelvin played a major role in the engineering of the first transatlantic telegraph cable.<ref>Huurdeman, pp. 95–96</ref> Conversely, the engineer Oliver Heaviside produced major work on the mathematics of transmission on telegraph cables.<ref>Huurdeman, p. 90</ref> Electrical engineers are often required on major science projects. For instance, large particle accelerators such as CERN need electrical engineers to deal with many aspects of the project including the power distribution, the instrumentation, and the manufacture and installation of the superconducting electromagnets.<ref>Schmidt, p. 218</ref><ref>Martini, p. 179</ref>

See also

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Notes

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References

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Bibliography

Further reading

Library resources about
Electrical engineering

External links

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