Technical knowledge, management skills, advanced mathematics, systems design, physics, science, abstract thinking, analytical thinking, philosophy of logic (see alsoGlossary of electrical and electronics engineering)
Electrical engineers work in a very wide range of industries and the skills required are likewise variable. These range fromcircuit theory to the management skills of aproject manager. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simplevoltmeter to sophisticated design and manufacturing software.
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 betweenmagnetism andstatic electricity. He is credited with establishing the term "electricity".[1] He also designed theversorium: a device that detects the presence of statically charged objects. In 1762 Swedish professorJohan Wilcke invented a device later namedelectrophorus that produced a static electric charge.[2] By 1800Alessandro Volta had developed thevoltaic pile, a forerunner of the electric battery.
In 1782,Georges-Louis Le Sage developed and presented inBerlin probably the world's first form ofelectric 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.[4]Electrical telegraphy may be considered the first example of electrical engineering.[5] Electrical engineering became a profession in the later 19th century. Practitioners had created a globalelectric 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.[6][7] Over 50 years later, he joined the new Society of Telegraph Engineers (soon to be renamed theInstitution of Electrical Engineers) where he was regarded by other members as the first of their cohort.[8] 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 standardizedunits of measure. They led to the international standardization of the unitsvolt,ampere,coulomb,ohm,farad, andhenry. This was achieved at an international conference inChicago in 1893.[9] 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.[10]
During these years, the study of electricity was largely considered to be a subfield ofphysics since early electrical technology was consideredelectromechanical in nature. TheTechnische Universität Darmstadt founded the world's first department of electrical engineering in 1882 and introduced the first-degree course in electrical engineering in 1883.[11] The first electrical engineering degree program in the United States was started atMassachusetts Institute of Technology (MIT) in the physics department under Professor Charles Cross,[12] though it wasCornell University to produce the world's first electrical engineering graduates in 1885.[13] The first course in electrical engineering was taught in 1883 in Cornell'sSibley College of Mechanical Engineering and Mechanic Arts.[14]
In about 1885, Cornell PresidentAndrew Dickson White established the first Department of Electrical Engineering in the United States.[15] In the same year,University College London founded the first chair of electrical engineering in Great Britain.[16] Professor Mendell P. Weinbach atUniversity of Missouri established the electrical engineering department in 1886.[17] Afterwards, universities andinstitutes of technology gradually started to offer electrical engineering programs to their students all over the world.
During thedevelopment of radio, many scientists and inventors contributed toradio technology and electronics. The mathematical work ofJames Clerk Maxwell during the 1850s had shown the relationship of different forms ofelectromagnetic 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 transmittingradio waves with aspark-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 commercialwireless 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).[22]
In 1920,Albert Hull developed themagnetron which would eventually lead to the development of themicrowave oven in 1946 byPercy Spencer.[29][30] In 1934, theBritish military began to make strides towardradar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station atBawdsey in August 1936.[31]
In 1941,Konrad Zuse presented theZ3, the world's first fully functional and programmable computer using electromechanical parts. In 1943,Tommy Flowers designed and built theColossus, the world's first fully functional, electronic, digital and programmable computer.[32][33] In 1946, theENIAC (Electronic Numerical Integrator and Computer) ofJohn Presper Eckert andJohn Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives.[34]
In 1948,Claude Shannon published "A Mathematical Theory of Communication" which mathematically describes the passage of information with uncertainty (electrical noise).
TheMOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) was invented byMohamed Atalla andDawon Kahng at BTL in 1959.[40][41][42] It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses.[37] It revolutionized theelectronics industry,[43][44] becoming the most widely used electronic device in the world.[41][45][46]
The MOSFET made it possible to buildhigh-density integrated circuit chips.[41] The earliest experimental MOS IC chip to be fabricated was built by Fred Heiman and Steven Hofstein atRCA Laboratories in 1962.[47] MOS technology enabledMoore's law, thedoubling of transistors on an IC chip every two years, predicted byGordon Moore in 1965.[48]Silicon-gate MOS technology was developed byFederico Faggin at Fairchild in 1968.[49] Since then, the MOSFET has been the basic building block of modern electronics.[42][50][51] The mass-production of silicon MOSFETs and MOS integrated circuit chips, along with continuousMOSFET scaling miniaturization at an exponential pace (as predicted byMoore's law), has since led to revolutionary changes in technology, economy, culture and thinking.[52]
The development of MOS integrated circuit technology in the 1960s led to the invention of themicroprocessor in the early 1970s.[56][57] The first single-chip microprocessor was theIntel 4004, released in 1971.[56] The Intel 4004 was designed and realized by Federico Faggin at Intel with his silicon-gate MOS technology,[56] along with Intel'sMarcian Hoff andStanley Mazor and Busicom's Masatoshi Shima.[58] The microprocessor led to the development ofmicrocomputers and personal computers, and themicrocomputer revolution.
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 aselectronic engineering andcomputer engineering, are considered disciplines in their own right.
Power & Energy engineering deals with thegeneration,transmission, anddistribution of electricity as well as the design of a range of related devices.[59] These includetransformers,electric generators,electric motors, high voltage engineering, andpower electronics. In many regions of the world, governments maintain an electrical network called apower 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.[60] Such systems are calledon-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, calledoff-grid power systems, which in some cases are preferable to on-grid systems.
Satellite dishes are a crucial component in the analysis of satellite information.
Telecommunications engineering focuses on thetransmission of information across acommunication channel such as acoax cable,optical fiber orfree space.[61] Transmissions across free space require information to be encoded in acarrier signal to shift the information to a carrier frequency suitable for transmission; this is known asmodulation. Popular analog modulation techniques includeamplitude modulation andfrequency modulation.[62] 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 thetransmitters andreceivers needed for such systems. These two are sometimes combined to form a two-way communication device known as atransceiver. A key consideration in the design of transmitters is theirpower consumption as this is closely related to theirsignal strength.[63][64] 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 bynoise, specifically static.
Control engineers often usefeedback when designingcontrol systems. For example, in anautomobile withcruise control the vehicle'sspeed is continuously monitored and fed back to the system which adjusts themotor'spower output accordingly.[67] Where there is regular feedback,control theory can be used to determine how the system responds to such feedback.
Control engineers also work inrobotics to design autonomous systems using control algorithms which interpret sensory feedback to control actuators that move robots such asautonomous vehicles, autonomous drones and others used in a variety of industries.[68]
Electronic engineering involves the design and testing ofelectronic circuits that use the properties ofcomponents such asresistors,capacitors,inductors,diodes, andtransistors to achieve a particular functionality.[60] Thetuned circuit, which allows the user of a radio tofilter 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 asradio engineering and basically was restricted to aspects of communications andradar,commercial radio, andearly television.[60] Later, in post-war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers, andmicroprocessors. In the mid-to-late 1950s, the termradio engineering gradually gave way to the nameelectronic engineering.
Before the invention of theintegrated circuit in 1959,[69] electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space andpower 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, mainlytransistors,[70] into a small chip around the size of acoin. This allowed for the powerful computers and other electronic devices we see today.
Microelectronics engineering deals with the design andmicrofabrication of very small electronic circuit components for use in anintegrated circuit or sometimes for use on their own as a general electronic component.[71] The most common microelectronic components aresemiconductortransistors, although all main electronic components (resistors,capacitors etc.) can be created at a microscopic level.
Nanoelectronics is the further scaling of devices down tonanometer levels. Modern devices are already in the nanometer regime, with below 100 nm processing having been standard since around 2002.[72]
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 ofquantum mechanics.[73]
ABayer filter on aCCD requires signal processing to get a red, green, and blue value at each pixel.
Signal processing deals with the analysis and manipulation ofsignals.[74] Signals can be eitheranalog, in which case the signal varies continuously according to the information, ordigital, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve theamplification andfiltering of audio signals for audio equipment or themodulation anddemodulation of signals for telecommunications. For digital signals, signal processing may involve thecompression,error detection anderror correction of digitally sampled signals.[75]
Signal processing is a very mathematically oriented and intensive area forming the core ofdigital 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, andbiomedical engineering as many already existing analog systems are replaced with their digital counterparts.Analog signal processing is still important in the design of manycontrol systems.
Often instrumentation is not used by itself, but instead as thesensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant.[80] For this reason, instrumentation engineering is often viewed as the counterpart of control.
Computer engineering deals with the design of computers andcomputer systems. This may involve the design of newhardware. 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.[81]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 ofembedded devices includingvideo game consoles andDVD players. Computer engineers are involved in many hardware and software aspects of computing.[82]Robots are one of the applications of computer engineering.
Electromagnetic spectrum showing wavelengths from radio waves (1 km) to gamma rays (0.01 nm). Visible light Information transmission in electrical engineering applications most frequently usesinfrared light in theC band (1530–1565 nm).
The termmechatronics is typically used to refer tomacroscopic systems butfuturists have predicted the emergence of very small electromechanical devices. Already, such small devices, known asmicroelectromechanical systems (MEMS), are used in automobiles to tellairbags when to deploy,[87] indigital projectors to create sharper images, and ininkjet printers to create nozzles for high definition printing. In the future it is hoped the devices will help build tiny implantable medical devices and improveoptical communication.[88]
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.[93]
Some electrical engineers choose to study for a postgraduate degree such as aMaster of Engineering/Master of Science (MEng/MSc), a Master ofEngineering Management, a Doctor of Philosophy (PhD) in Engineering, anEngineering Doctorate (Eng.D.), or anEngineer'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 toacademia. 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.[94]
Belgian electrical engineers inspecting the rotor of a 40,000 kilowattturbine of theGeneral Electric Company in New York City
In most countries, a bachelor's degree in engineering represents the first step towardsprofessional certification and the degree program itself is certified by aprofessional body.[95] 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 ofProfessional Engineer (in the United States, Canada and South Africa),Chartered engineer orIncorporated Engineer (in India, Pakistan, the United Kingdom, Ireland andZimbabwe), Chartered Professional Engineer (in Australia and New Zealand) orEuropean Engineer (in much of theEuropean Union).
TheIEEE corporate office is on the 17th floor of3 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".[96] This requirement is enforced by state and provincial legislation such asQuebec's Engineers Act.[97] In other countries, no such legislation exists. Practically all certifying bodies maintain acode of ethics that they expect all members to abide by or risk expulsion.[98] 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 tocontract law. In cases where an engineer's work fails he or she may be subject to thetort of negligence and, in extreme cases, the charge ofcriminal negligence. An engineer's work must also comply with numerous other rules and regulations, such asbuilding codes and legislation pertaining toenvironmental law.
Professional bodies of note for electrical engineers include theInstitute of Electrical and Electronics Engineers (IEEE) and theInstitution 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.[99] The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.[100][101] 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.[102]
In Australia, Canada, and the United States, electrical engineers make up around 0.25% of the labor force.[b]
From theGlobal Positioning System toelectric 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 telecommunications systems, the operation ofelectric power stations, thelighting andwiring of buildings, the design ofhousehold appliances, or the electricalcontrol of industrial machinery.[106]
Fundamental to the discipline are the sciences ofphysics and mathematics as these help to obtain both aqualitative andquantitative description of how such systems will work. Today most engineering work involves the use ofcomputers and it is commonplace to usecomputer-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 basiccircuit theory (that is, the interactions of elements such asresistors,capacitors,diodes,transistors, andinductors in a circuit), the theories employed by engineers generally depend upon the work they do. For example,quantum mechanics andsolid state physics might be relevant to an engineer working onVLSI (the design of integrated circuits), but are largely irrelevant to engineers working with macroscopic electrical systems. Evencircuit theory may not be relevant to a person designing telecommunications systems that useoff-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasizestrong numerical skills,computer literacy, and the ability to understand thetechnical language and concepts that relate to electrical engineering.[107]
A wide range of instrumentation is used by electrical engineers. For simple control circuits and alarms, a basicmultimeter measuringvoltage,current, andresistance may suffice. Where time-varying signals need to be studied, theoscilloscope is also an ubiquitous instrument. InRF engineering and high-frequency telecommunications,spectrum analyzers andnetwork 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.[108] Power transmission engineering also has great safety concerns due to the high voltages used; althoughvoltmeters may in principle be similar to their low voltage equivalents, safety and calibration issues make them very different.[109] Many disciplines of electrical engineering use tests specific to their discipline. Audio electronics engineers useaudio test sets consisting of a signal generator and a meter, principally to measure level but also other parameters such asharmonic distortion andnoise. 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, preparingbudgets and determiningproject schedules.[110] Many senior engineers manage a team oftechnicians or other engineers and for this reasonproject management skills are important. Most engineering projects involve some form of documentation andstrong written communication skills are therefore very important.
Theworkplaces of engineers are just as varied as the types of work they do. Electrical engineers may be found in the pristine lab environment of afabrication plant, on board aNaval ship, the offices of aconsulting 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.[111]
Electrical engineering has an intimate relationship with the physical sciences. For instance, the physicistLord Kelvin played a major role in the engineering of the firsttransatlantic telegraph cable.[112] Conversely, the engineerOliver Heaviside produced major work on the mathematics of transmission on telegraph cables.[113] Electrical engineers are often required on major science projects. For instance, largeparticle accelerators such asCERN need electrical engineers to deal with many aspects of the project including the power distribution, the instrumentation, and the manufacture and installation of thesuperconducting electromagnets.[114][115]
^In May 2014 there were around 175,000 people working as electrical engineers in the US.[103] In 2012, Australia had around 19,000[104] while in Canada, there were around 37,000 (as of 2007[update]), 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.[105]
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^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.S2CID20662894.
^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.ISBN978-0-262-68137-7.
^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.ISBN978-0-262-68137-7.
^Grant, Duncan Andrew; Gowar, John (1989).Power MOSFETS: theory and applications.Wiley. p. 1.ISBN9780471828679.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.
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IEEE Global History Network A wiki-based site with many resources about the history of IEEE, its members, their professions and electrical and informational technologies and sciences.
