\n\n\n
<\/p>\n\n\n<\/p>\n
Electrical engineering is now divided into a wide range of different fields, including computer engineering<\/a>, systems engineering<\/a>, power engineering<\/a>, telecommunications, radio-frequency engineering<\/a>, signal processing<\/a>, instrumentation<\/a>, photovoltaic cells<\/a>, electronics<\/a>, and optics<\/a> and photonics<\/a>. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering, power electronics<\/a>, electromagnetics and waves, microwave engineering<\/a>, nanotechnology<\/a>, electrochemistry<\/a>, renewable energies, mechatronics\/control, and electrical materials science.[a]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Electrical engineers typically hold a degree<\/a> in electrical engineering or electronic engineering. Practising engineers may have professional certification<\/a> and be members of a professional body<\/a> or an international standards organization. These include the International Electrotechnical Commission<\/a> (IEC), the Institute of Electrical and Electronics Engineers<\/a> (IEEE) and the Institution of Engineering and Technology<\/a> (IET) (formerly the IEE)<\/em>.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range from circuit theory<\/a> to the management skills of a project manager<\/a>. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple voltmeter<\/a> to sophisticated design and manufacturing software.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Main article: History of electrical engineering<\/a><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Electricity has been a subject of scientific interest since at least the early-17th-century. William Gilbert<\/a> was a prominent early electrical scientist, and was the first to draw a clear distinction between magnetism<\/a> and static electricity<\/a>. He is credited with establishing the term “electricity”.[1]<\/a><\/sup> He also designed the versorium<\/a>: a device that detects the presence of statically charged objects. In 1762 Swedish professor Johan Wilcke<\/a> invented a device later named electrophorus<\/a> that produced a static electric charge. By 1800 Alessandro Volta<\/a> had developed the voltaic pile<\/a>, a forerunner of the electric battery.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n <\/a><\/a>The discoveries of Michael Faraday<\/a> formed the foundation of electric motor technology.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of Hans Christian \u00d8rsted<\/a> who discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle, of William Sturgeon<\/a> who, in 1825 invented the electromagnet<\/a>, of Joseph Henry<\/a> and Edward Davy<\/a> who invented the electrical relay<\/a> in 1835, of Georg Ohm<\/a>, who in 1827 quantified the relationship between the \n\n\n <\/p>\n\n\n<\/p>\n In 1782, Georges-Louis Le Sage<\/a> developed and presented in Berlin<\/a> 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.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In 1795, Francisco Salva Campillo<\/a> 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 new discoveries made in Europe in 1800 \u2013 Alessandro Volta’s electric battery for generating an electric current and William Nicholson and Anthony Carlyle’s electrolysis of water.[4]<\/a><\/sup> Electrical telegraphy<\/a> may be considered the first example of electrical engineering.[5]<\/a><\/sup> Electrical engineering became a profession in the later 19th century. Practitioners had created a global electric telegraph<\/a> network, and the first professional electrical engineering institutions were founded in the UK and USA to support the new discipline. Francis Ronalds<\/a> created an electric telegraph system in 1816 and documented his vision of how the world could be transformed by electricity.[6]<\/a><\/sup>[7]<\/a><\/sup> Over 50 years later, he joined the new Society of Telegraph Engineers (soon to be renamed the Institution of Electrical Engineers<\/a>) where he was regarded by other members as the first of their cohort.[8]<\/a><\/sup> 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<\/a>, and, from about 1890, wireless telegraphy<\/a>.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Practical applications and advances in such fields created an increasing need for standardised units of measure<\/a>. They led to the international standardization of the units volt<\/a>, ampere<\/a>, coulomb<\/a>, ohm<\/a>, farad<\/a>, and henry<\/a>. This was achieved at an international conference in Chicago in 1893.[9]<\/a><\/sup> The publication of these standards formed the basis of future advances in standardisation in various industries, and in many countries, the definitions were immediately recognized in relevant legislation.[10]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n During these years, the study of electricity was largely considered to be a subfield of physics<\/a> since the early electrical technology was considered electromechanical<\/a> in nature. The Technische Universit\u00e4t Darmstadt<\/a> founded the world’s first department of electrical engineering in 1882 and introduced the first degree course in electrical engineering in 1883.[11]<\/a><\/sup> The first electrical engineering degree program in the United States was started at Massachusetts Institute of Technology<\/a> (MIT) in the physics department under Professor Charles Cross, [12]<\/a><\/sup> though it was Cornell University<\/a> to produce the world’s first electrical engineering graduates in 1885.[13]<\/a><\/sup> The first course in electrical engineering was taught in 1883 in Cornell’s Sibley College of Mechanical Engineering and Mechanic Arts<\/a>.[14]<\/a><\/sup> It was not until about 1885 that Cornell President Andrew Dickson White<\/a> established the first Department of Electrical Engineering in the United States.[15]<\/a><\/sup> In the same year, University College London<\/a> founded the first chair of electrical engineering in Great Britain.[16]<\/a><\/sup> Professor Mendell P. Weinbach at University of Missouri<\/a> soon followed suit by establishing the electrical engineering department in 1886.[17]<\/a><\/sup> Afterwards, universities and institutes of technology<\/a> gradually started to offer electrical engineering programs to their students all over the world.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n During these decades use of electrical engineering increased dramatically. In 1882, Thomas Edison<\/a> switched on the world’s first large-scale electric power network that provided 110 volts \u2014 direct current<\/a> (DC) \u2014 to 59 customers on Manhattan Island<\/a> in New York City. In 1884, Sir Charles Parsons<\/a> invented the steam turbine<\/a> allowing for more efficient electric power generation. Alternating current<\/a>, with its ability to transmit power more efficiently over long distances via the use of transformers<\/a>, developed rapidly in the 1880s and 1890s with transformer designs by K\u00e1roly Zipernowsky<\/a>, Ott\u00f3 Bl\u00e1thy<\/a> and Miksa D\u00e9ri<\/a> (later called ZBD transformers), Lucien Gaulard<\/a>, John Dixon Gibbs<\/a> and William Stanley, Jr.<\/a> Practical AC motor<\/a> designs including induction motors<\/a> were independently invented by Galileo Ferraris<\/a> and Nikola Tesla<\/a> and further developed into a practical three-phase<\/a> form by Mikhail Dolivo-Dobrovolsky<\/a> and Charles Eugene Lancelot Brown<\/a>.[18]<\/a><\/sup> Charles Steinmetz<\/a> and Oliver Heaviside<\/a> contributed to the theoretical basis of alternating current engineering.[19]<\/a><\/sup>[20]<\/a><\/sup> The spread in the use of AC set off in the United States what has been called the war of the currents<\/a><\/em> between a George Westinghouse<\/a> backed AC system and a Thomas Edison backed DC power system, with AC being adopted as the overall standard.[21]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n <\/a><\/a>Guglielmo Marconi<\/a>, known for his pioneering work on long-distance radio transmission<\/a><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n During the development of radio<\/a>, many scientists and inventors contributed to radio technology<\/a> and electronics. The mathematical work of James Clerk Maxwell<\/a> during the 1850s had shown the relationship of different forms of electromagnetic radiation<\/a> including the possibility of invisible airborne waves (later called “radio waves”). In his classic physics experiments of 1888, Heinrich Hertz<\/a> proved Maxwell’s theory by transmitting radio waves<\/a> with a spark-gap transmitter<\/a>, 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<\/a> began work on a way to adapt the known methods of transmitting and detecting these “Hertzian waves” into a purpose built commercial wireless telegraphic<\/a> 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).[22]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Millimetre wave<\/a> communication was first investigated by Jagadish Chandra Bose<\/a> during 1894\u20131896, when he reached an extremely high frequency<\/a> of up to 60 GHz<\/a> in his experiments.[23]<\/a><\/sup> He also introduced the use of semiconductor<\/a> junctions to detect radio waves,[24]<\/a><\/sup> when he patented the radio crystal detector<\/a> in 1901.[25]<\/a><\/sup>[26]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In 1897, Karl Ferdinand Braun<\/a> introduced the cathode ray tube<\/a> as part of an oscilloscope<\/a>, a crucial enabling technology for electronic television<\/a>.[27]<\/a><\/sup> John Fleming<\/a> invented the first radio tube, the diode<\/a>, in 1904. Two years later, Robert von Lieben<\/a> and Lee De Forest<\/a> independently developed the amplifier tube, called the triode<\/a>.[28]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In 1920, Albert Hull<\/a> developed the magnetron<\/a> which would eventually lead to the development of the microwave oven<\/a> in 1946 by Percy Spencer<\/a>.[29]<\/a><\/sup>[30]<\/a><\/sup> In 1934, the British military began to make strides toward radar<\/a> (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey<\/a> in August 1936.[31]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In 1941, Konrad Zuse<\/a> presented the Z3<\/a>, the world’s first fully functional and programmable computer using electromechanical parts. In 1943, Tommy Flowers<\/a> designed and built the Colossus<\/a>, the world’s first fully functional, electronic, digital and programmable computer.[32]<\/a><\/sup>[33]<\/a><\/sup> In 1946, the ENIAC<\/a> (Electronic Numerical Integrator and Computer) of John Presper Eckert<\/a> and John Mauchly<\/a> followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives.[34]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n In 1948 Claude Shannon<\/a> publishes “A Mathematical Theory of Communication” which mathematically describes the passage of information with uncertainty (electrical noise<\/a>).<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n See also: History of electronic engineering<\/a>, History of the transistor<\/a>, Invention of the integrated circuit<\/a>, MOSFET<\/a>, and Solid-state electronics<\/a><\/a><\/a>A replica of the first working transistor<\/a>, a point-contact transistor<\/a><\/a><\/a>Metal\u2013oxide\u2013semiconductor field-effect transistor<\/a> (MOSFET), the basic building block of modern electronics<\/a><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The first working transistor<\/a> was a point-contact transistor<\/a> invented by John Bardeen<\/a> and Walter Houser Brattain<\/a> while working under William Shockley<\/a> at the Bell Telephone Laboratories<\/a> (BTL) in 1947.[35]<\/a><\/sup> They then invented the bipolar junction transistor<\/a> in 1948.[36]<\/a><\/sup> While early junction transistors<\/a> were relatively bulky devices that were difficult to manufacture on a mass-production<\/a> basis,[37]<\/a><\/sup> they opened the door for more compact devices.[38]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The first integrated circuits<\/a> were the hybrid integrated circuit<\/a> invented by Jack Kilby<\/a> at Texas Instruments<\/a> in 1958 and the monolithic integrated circuit chip invented by Robert Noyce<\/a> at Fairchild Semiconductor<\/a> in 1959.[39]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The MOSFET<\/a> (metal-oxide-semiconductor field-effect transistor, or MOS transistor) was invented by Mohamed Atalla<\/a> and Dawon Kahng<\/a> at BTL in 1959.[40]<\/a><\/sup>[41]<\/a><\/sup>[42]<\/a><\/sup> It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses.[37]<\/a><\/sup> It revolutionized the electronics industry<\/a>,[43]<\/a><\/sup>[44]<\/a><\/sup> becoming the most widely used electronic device in the world.[41]<\/a><\/sup>[45]<\/a><\/sup>[46]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The MOSFET made it possible to build high-density integrated circuit<\/a> chips.[41]<\/a><\/sup> The earliest experimental MOS IC chip to be fabricated was built by Fred Heiman and Steven Hofstein at RCA Laboratories<\/a> in 1962.[47]<\/a><\/sup> MOS technology enabled Moore’s law<\/a>, the doubling of transistors<\/a> on an IC chip every two years, predicted by Gordon Moore<\/a> in 1965.[48]<\/a><\/sup> Silicon-gate<\/a> MOS technology was developed by Federico Faggin<\/a> at Fairchild in 1968.[49]<\/a><\/sup> Since then, the MOSFET has been the basic building block of modern electronics.[42]<\/a><\/sup>[50]<\/a><\/sup>[51]<\/a><\/sup> The mass-production of silicon MOSFETs and MOS integrated circuit chips, along with continuous MOSFET scaling<\/a> miniaturization at an exponential pace (as predicted by Moore’s law<\/a>), has since led to revolutionary changes in technology, economy, culture and thinking.[52]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The Apollo program<\/a> which culminated in landing astronauts on the Moon<\/a> with Apollo 11<\/a> in 1969 was enabled by NASA<\/a>‘s adoption of advances in semiconductor<\/a> electronic technology<\/a>, including MOSFETs in the Interplanetary Monitoring Platform<\/a> (IMP)[53]<\/a><\/sup>[54]<\/a><\/sup> and silicon integrated circuit chips in the Apollo Guidance Computer<\/a> (AGC).[55]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n The development of MOS integrated circuit technology in the 1960s led to the invention of the microprocessor<\/a> in the early 1970s.[56]<\/a><\/sup>[57]<\/a><\/sup> The first single-chip microprocessor was the Intel 4004<\/a>, released in 1971.[56]<\/a><\/sup> The Intel 4004 was designed and realized by Federico Faggin at Intel with his silicon-gate MOS technology,[56]<\/a><\/sup> along with Intel’s Marcian Hoff<\/a> and Stanley Mazor<\/a> and Busicom’s Masatoshi Shima.[58]<\/a><\/sup> The microprocessor led to the development of microcomputers<\/a> and personal computers, and the microcomputer revolution<\/a>.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n 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<\/a>, are considered disciplines in their own right.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Main articles: Power engineering<\/a> and Energy engineering<\/a><\/a><\/a>The top of a power pole<\/a><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Power & Energy engineering deals with the generation<\/a>, transmission<\/a>, and distribution<\/a> of electricity as well as the design of a range of related devices.[59]<\/a><\/sup> These include transformers<\/a>, electric generators<\/a>, electric motors<\/a>, high voltage engineering, and power electronics<\/a>. In many regions of the world, governments maintain an electrical network called a power grid<\/a> 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.[60]<\/a><\/sup> Such systems are called on-grid<\/em> 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<\/em> 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.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Main article: Telecommunications engineering<\/a><\/a><\/a>Satellite dishes<\/a> are a crucial component in the analysis of satellite information.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Telecommunications engineering focuses on the transmission<\/a> of information across a communication channel<\/a> such as a coax cable<\/a>, optical fiber<\/a> or free space<\/a>.[61]<\/a><\/sup> Transmissions across free space require information to be encoded in a carrier signal<\/a> to shift the information to a carrier frequency suitable for transmission; this is known as modulation<\/a>. Popular analog modulation techniques include amplitude modulation<\/a> and frequency modulation<\/a>.[62]<\/a><\/sup> The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Once the transmission characteristics of a system are determined, telecommunication engineers design the transmitters<\/a> and receivers<\/a> needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver<\/a>. A key consideration in the design of transmitters is their power consumption<\/a> as this is closely related to their signal strength<\/a>.[63]<\/a><\/sup>[64]<\/a><\/sup> 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<\/a>, specifically static.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Main articles: Control engineering<\/a> and Control theory<\/a><\/a><\/a>Control systems<\/a> play a critical role in spaceflight<\/a>.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Control engineering<\/a> focuses on the modeling<\/a> of a diverse range of dynamic systems<\/a> and the design of controllers<\/a> that will cause these systems to behave in the desired manner.[65]<\/a><\/sup> To implement such controllers, electronics control engineers may use electronic circuits<\/a>, digital signal processors<\/a>, microcontrollers<\/a>, and programmable logic controllers<\/a> (PLCs). Control engineering<\/a> has a wide range of applications from the flight and propulsion systems of commercial airliners<\/a> to the cruise control<\/a> present in many modern automobiles<\/a>.[66]<\/a><\/sup> It also plays an important role in industrial automation<\/a>.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Control engineers often use feedback<\/a> when designing control systems<\/a>. For example, in an automobile<\/a> with cruise control<\/a> the vehicle’s speed<\/a> is continuously monitored and fed back to the system which adjusts the motor’s<\/a> power<\/a> output accordingly.[67]<\/a><\/sup> Where there is regular feedback, control theory<\/a> can be used to determine how the system responds to such feedback.<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Control engineers also work in robotics<\/a> to design autonomous systems using control algorithms which interpret sensory feedback to control actuators that move robots such as autonomous vehicles<\/a>, autonomous drones and others used in a variety of industries.[68]<\/a><\/sup><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Main article: Electronic engineering<\/a><\/a><\/a>Electronic components<\/a><\/p>\n \n\n\n <\/p>\n\n\n<\/p>\n Electronic engineering involves the design and testing of electronic circuits<\/a> that use the properties of components<\/a> such as resistors<\/a>, capacitors<\/a>, inductors<\/a>, diodes<\/a>, and transistors<\/a> to achieve a particular functionality.History[edit<\/a>]<\/h2>\n
19th century[edit<\/a>]<\/h3>\n
![\"\ud83d\udc7b\"](\"https:\/\/s.w.org\/images\/core\/emoji\/13.1.0\/svg\/1f47b.svg\")
electric current<\/a> and potential difference<\/a> in a conductor<\/a>,[2]<\/a><\/sup> of Michael Faraday<\/a> (the discoverer of electromagnetic induction<\/a> in 1831), and of James Clerk Maxwell<\/a>, who in 1873 published a unified theory<\/a> of electricity and magnetism<\/a> in his treatise Electricity and Magnetism<\/em>.[3]<\/a><\/sup><\/p>\nEarly 20th century[edit<\/a>]<\/h3>\n
Solid-state electronics[edit<\/a>]<\/h3>\n
Subfields[edit<\/a>]<\/h2>\n
Power and energy[edit<\/a>]<\/h3>\n
Telecommunications[edit<\/a>]<\/h3>\n
Control engineering[edit<\/a>]<\/h3>\n
Electronics[edit<\/a>]<\/h3>\n
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