Electrical engineering is an
engineering
Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, s ...
discipline concerned with the study, design, and application of equipment, devices, and systems that use
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...
,
electronics
Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other Electric charge, electrically charged particles. It is a subfield ...
, and
electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
. It emerged as an identifiable occupation in the latter half of the 19th century after the
commercialization
Commercialisation or commercialization is the process of introducing a new product or production method into commerce—making it available on the market. The term often connotes especially entry into the mass market (as opposed to entry into e ...
of the
electric telegraph
Electrical telegraphy is Point-to-point (telecommunications), point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecom ...
, the telephone, and
electrical power
Electric power is the rate of transfer of electrical energy within a electric circuit, circuit. Its SI unit is the watt, the general unit of power (physics), power, defined as one joule per second. Standard prefixes apply to watts as with oth ...
generation, distribution, and use.
Electrical engineering is divided into a wide range of different fields, including
computer engineering
Computer engineering (CE, CoE, or CpE) is a branch of engineering specialized in developing computer hardware and software.
It integrates several fields of electrical engineering, electronics engineering and computer science.
Computer engi ...
,
systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
,
power engineering
Power engineering, also called power systems engineering, is a subfield of electrical engineering that deals with the generation, transmission, distribution, and utilization of electric power, and the electrical apparatus connected to such sy ...
,
telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...
,
radio-frequency engineering
Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, Waveguide (electromagnetism), waveguide, Antenna (radio), antenna, radar, and Electromagnetic radiation, electromagnetic fiel ...
,
signal processing
Signal processing is an electrical engineering subfield that focuses on analyzing, modifying and synthesizing ''signals'', such as audio signal processing, sound, image processing, images, Scalar potential, potential fields, Seismic tomograph ...
,
instrumentation
Instrumentation is a collective term for measuring instruments, used for indicating, measuring, and recording physical quantities. It is also a field of study about the art and science about making measurement instruments, involving the related ...
,
photovoltaic cell
A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect. s,
electronics
Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other Electric charge, electrically charged particles. It is a subfield ...
, and
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...
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
Nanotechnology is the manipulation of matter with at least one dimension sized from 1 to 100 nanometers (nm). At this scale, commonly known as the nanoscale, surface area and quantum mechanical effects become important in describing propertie ...
,
electrochemistry
Electrochemistry is the branch of physical chemistry concerned with the relationship between Electric potential, electrical potential difference and identifiable chemical change. These reactions involve Electron, electrons moving via an electronic ...
, renewable energies, mechatronics/control, and electrical materials science.
Electrical engineers typically hold a
degree in electrical engineering, electronic or electrical and electronic engineering. Practicing engineers may have
professional certification
Professional certification, trade certification, or professional designation, often called simply ''certification'' or ''qualification'', is a designation earned by a person to assure qualification to perform a job or task. Not all certifications ...
and be members of a
professional body
A professional association (also called a professional body, professional organization, or professional society) is a group that usually seeks to advocacy, further a particular profession, the interests of individuals and organisations engaged in ...
or an international standards organization. These include the
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronics, electronic and related technologies. IEC standards cover a va ...
(IEC), the
National Society of Professional Engineers (NSPE), the
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines.
The IEEE has a corporate office ...
(IEEE) and the
Institution of Engineering and Technology
The Institution of Engineering and Technology (IET) is a multidisciplinary professional engineering institution. The IET was formed in 2006 from two separate institutions: the Institution of Electrical Engineers (IEE), dating back to 1871,Engin ...
(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
A project manager is a professional in the field of project management. Project managers have the responsibility of the Project planning, planning, procurement and execution of a project, in any undertaking that has a defined scope, defined star ...
. The tools and equipment that an individual engineer may need are similarly variable, ranging from a simple
voltmeter
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit.
A ...
to sophisticated design and manufacturing software.
History
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
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, ...
and
static electricity
Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it can move away by an electric current or electrical discharge. The word "static" is used to differentiate it from electric ...
. He is credited with establishing the term "electricity". 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
In electromagnetism, an electrophorus or electrophore is a simple, manual, Capacitor, capacitive, electrostatic generator used to produce Electric charge, charge via the process of electrostatic induction. A first version of it was invented in 1 ...
that produced a static electric charge. By 1800
Alessandro Volta
Alessandro Giuseppe Antonio Anastasio Volta (, ; ; 18 February 1745 – 5 March 1827) was an Italian chemist and physicist who was a pioneer of electricity and Power (physics), power, and is credited as the inventor of the electric battery a ...
had developed the
voltaic pile, a forerunner of the electric battery.
19th century

In the 19th century, research into the subject started to intensify. Notable developments in this century include the work of
Hans Christian Ørsted
Hans Christian Ørsted (; 14 August 1777 – 9 March 1851), sometimes Transliteration, transliterated as Oersted ( ), was a Danish chemist and physicist who discovered that electric currents create magnetic fields. This phenomenon is known as ...
, who discovered in 1820 that an electric current produces a magnetic field that will deflect a compass needle; of
William Sturgeon
William Sturgeon (; 22 May 1783 – 4 December 1850) was an English electrical engineer and inventor who made the first electromagnet and the first practical electric motor.
Early life
Sturgeon was born on 22 May 1783 in Whittington, near ...
, who in 1825 invented the
electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire (likely copper) wound into a electromagnetic coil, coil. A current through the wire creates a magnetic ...
; of
Joseph Henry
Joseph Henry (December 17, 1797– May 13, 1878) was an American physicist and inventor who served as the first secretary of the Smithsonian Institution. He was the secretary for the National Institute for the Promotion of Science, a precursor ...
and
Edward Davy, who invented the
electrical relay in 1835; of
Georg Ohm
Georg Simon Ohm (; ; 16 March 1789 – 6 July 1854) was a German mathematician and physicist. As a school teacher, Ohm began his research with the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment of his o ...
, who in 1827 quantified the relationship between the
electric current
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge c ...
and
potential difference
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge ...
in a
conductor; of
Michael Faraday
Michael Faraday (; 22 September 1791 – 25 August 1867) was an English chemist and physicist who contributed to the study of electrochemistry and electromagnetism. His main discoveries include the principles underlying electromagnetic inducti ...
, the discoverer of
electromagnetic induction
Electromagnetic or magnetic induction is the production of an electromotive force, electromotive force (emf) across an electrical conductor in a changing magnetic field.
Michael Faraday is generally credited with the discovery of induction in 1 ...
in 1831; and of
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism an ...
, who in 1873 published a unified
theory
A theory is a systematic and rational form of abstract thinking about a phenomenon, or the conclusions derived from such thinking. It involves contemplative and logical reasoning, often supported by processes such as observation, experimentation, ...
of electricity and
magnetism
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, ...
in his treatise ''Electricity and Magnetism''.
In 1782,
Georges-Louis Le Sage developed and presented in
Berlin
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...
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.
Electrical telegraph
Electrical telegraphy is point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most wid ...
y may be considered the first example of electrical engineering. Electrical engineering became a profession in the later 19th century. Practitioners had created a global
electric telegraph
Electrical telegraphy is Point-to-point (telecommunications), point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecom ...
network, and the first professional electrical engineering institutions were founded in the UK and the US to support the new discipline.
Francis Ronalds
Sir Francis Ronalds Fellow of the Royal Society, FRS (21 February 17888 August 1873) was an English scientist and inventor, and arguably the first History of electrical engineering, electrical engineer. He was knighted for creating the first wo ...
created an electric telegraph system in 1816 and documented his vision of how the world could be transformed by electricity. Over 50 years later, he joined the new Society of Telegraph Engineers (soon to be renamed the
Institution of Electrical Engineers
The Institution of Electrical Engineers (IEE) was a British professional organisation of electronics, electrical, manufacturing, and information technology professionals, especially electrical engineers. It began in 1871 as the Society of Tel ...
) where he was regarded by other members as the first of their cohort. 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
Wireless telegraphy or radiotelegraphy is the transmission of text messages by radio waves, analogous to electrical telegraphy using electrical cable, cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimenta ...
.
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
The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...
,
ampere
The ampere ( , ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to 1 c ...
,
coulomb
The coulomb (symbol: C) is the unit of electric charge in the International System of Units (SI).
It is defined to be equal to the electric charge delivered by a 1 ampere current in 1 second, with the elementary charge ''e'' as a defining c ...
,
ohm
Ohm (symbol Ω) is a unit of electrical resistance named after Georg Ohm.
Ohm or OHM may also refer to:
People
* Georg Ohm (1789–1854), German physicist and namesake of the term ''ohm''
* Germán Ohm (born 1936), Mexican boxer
* Jörg Ohm (1 ...
,
farad
The farad (symbol: F) is the unit of electrical capacitance, the ability of a body to store an electrical charge, in the International System of Units, International System of Units (SI), equivalent to 1 coulomb per volt (C/V). It is named afte ...
, and
henry. This was achieved at an international conference in
Chicago
Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
in 1893. 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.
During these years, the study of electricity was largely considered to be a subfield of
physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
since early electrical technology was considered
electromechanical
Electromechanics combine processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focus on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each ...
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. The first electrical engineering degree program in the United States was started at
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...
(MIT) in the physics department under Professor Charles Cross, though it was
Cornell University
Cornell University is a Private university, private Ivy League research university based in Ithaca, New York, United States. The university was co-founded by American philanthropist Ezra Cornell and historian and educator Andrew Dickson W ...
to produce the world's first electrical engineering graduates in 1885. The first course in electrical engineering was taught in 1883 in Cornell's
Sibley College of Mechanical Engineering and Mechanic Arts.
In about 1885, Cornell President
Andrew Dickson White established the first Department of Electrical Engineering in the United States. In the same year,
University College London
University College London (Trade name, branded as UCL) is a Public university, public research university in London, England. It is a Member institutions of the University of London, member institution of the Federal university, federal Uni ...
founded the first chair of electrical engineering in Great Britain. Professor Mendell P. Weinbach at
University of Missouri
The University of Missouri (Mizzou or MU) is a public university, public Land-grant university, land-grant research university in Columbia, Missouri, United States. It is Missouri's largest university and the flagship of the four-campus Univers ...
established the electrical engineering department in 1886. 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
Thomas Alva Edison (February11, 1847October18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventions, ...
switched on the world's first large-scale electric power network that provided 110 volts—
direct current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...
(DC)—to 59 customers on
Manhattan Island
Manhattan ( ) is the most densely populated and geographically smallest of the five boroughs of New York City. Coextensive with New York County, Manhattan is the smallest county by area in the U.S. state of New York. Located almost entire ...
in New York City. In 1884,
Sir Charles Parsons
Sir Charles Algernon Parsons (13 June 1854 – 11 February 1931) was an Anglo-Irish people, Anglo-Irish mechanical engineer and inventor who designed the modern steam turbine in 1884. His invention revolutionised marine propulsion, and he was al ...
invented the
steam turbine
A steam turbine or steam turbine engine is a machine or heat engine that extracts thermal energy from pressurized steam and uses it to do mechanical work utilising a rotating output shaft. Its modern manifestation was invented by Sir Charles Par ...
allowing for more efficient electric power generation.
Alternating current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...
, with its ability to transmit power more efficiently over long distances via the use of
transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces ...
s, developed rapidly in the 1880s and 1890s with transformer designs by
Károly Zipernowsky,
Ottó Bláthy and
Miksa Déri (later called ZBD transformers),
Lucien Gaulard
Lucien Gaulard (16 July 1850 – 26 November 1888) was a French engineer who invented devices for the transmission of alternating current electrical energy.
Biography
Gaulard was born in Paris, France in 1850.
A power transformer developed by G ...
,
John Dixon Gibbs and
William Stanley Jr. Practical
AC motor designs including
induction motors were independently invented by
Galileo Ferraris
Galileo Ferraris (31 October 1847 – 7 February 1897) was an Italian university professor, physicist and electrical engineer, one of the pioneers of AC power system and inventor of the induction motor although he never patented his work. Many ne ...
and
Nikola Tesla
Nikola Tesla (;["Tesla"](_blank)
. ''Random House Webster's Unabridged Dictionary''. ; 10 July 1856 – 7 ...
and further developed into a practical
three-phase
Three-phase electric power (abbreviated 3ϕ) is a common type of alternating current (AC) used in electricity generation, Electric power transmission, transmission, and Electric power distribution, distribution. It is a type of polyphase system ...
form by
Mikhail Dolivo-Dobrovolsky and
Charles Eugene Lancelot Brown.
Charles Steinmetz and
Oliver Heaviside
Oliver Heaviside ( ; 18 May 1850 – 3 February 1925) was an English mathematician and physicist who invented a new technique for solving differential equations (equivalent to the Laplace transform), independently developed vector calculus, an ...
contributed to the theoretical basis of alternating current engineering. 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
George Westinghouse Jr. (October 6, 1846 – March 12, 1914) was a prolific American inventor, engineer, and entrepreneurial industrialist based in Pittsburgh, Pennsylvania. He is best known for his creation of the railway air brake and for bei ...
backed AC system and a Thomas Edison backed DC power system, with AC being adopted as the overall standard.
Early 20th century

During the
development of radio, many scientists and inventors contributed to
radio technology and electronics. The mathematical work of
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician who was responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism an ...
during the 1850s had shown the relationship of different forms of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
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 telegraphy, 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 .
Millimetre wave communication was first investigated by Jagadish Chandra Bose during 18941896, when he reached an extremely high frequency of up to 60GHz in his experiments. He also introduced the use of semiconductor junctions to detect radio waves,
[ reprinted in Igor Grigorov, Ed., ]
Antentop
', Vol. 2, No.3, pp. 87–96. when he patented the radio crystal detector in 1901.
In 1897, Karl Ferdinand Braun introduced the cathode-ray tube as part of an oscilloscope, a crucial enabling technology for television, electronic television. John Ambrose Fleming, John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.
In 1920, Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer. In 1934, the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.
In 1941, Konrad Zuse presented the Z3 (computer), Z3, the world's first fully functional and programmable computer using electromechanical parts. In 1943, Tommy Flowers designed and built the Colossus (computer), Colossus, the world's first fully functional, electronic, digital and programmable computer. In 1946, the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives.
In 1948, Claude Shannon published "A Mathematical Theory of Communication" which mathematically describes the passage of information with uncertainty (electrical noise).
Solid-state 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. They then invented the bipolar junction transistor in 1948. While early junction transistors were relatively bulky devices that were difficult to manufacture on a mass-production basis,
they opened the door for more compact devices.
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.
The MOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) was invented by Mohamed Atalla and Dawon Kahng at BTL in 1959.
It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses.
It revolutionized the electronics industry,
becoming the most widely used electronic device in the world.
The MOSFET made it possible to build very large-scale integration, high-density integrated circuit chips.
The earliest experimental MOS IC chip to be fabricated was built by Fred Heiman and Steven Hofstein at RCA Laboratories in 1962.
MOS technology enabled Moore's law, the transistor count, doubling of transistors on an IC chip every two years, predicted by Gordon Moore in 1965. Silicon-gate MOS technology was developed by Federico Faggin at Fairchild in 1968. Since then, the MOSFET has been the basic building block of modern electronics.
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.
The Apollo program which culminated in Moon landing, 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) and silicon integrated circuit chips in the Apollo Guidance Computer (AGC).
The development of MOS integrated circuit technology in the 1960s led to the invention of the microprocessor in the early 1970s.
The first single-chip microprocessor was the Intel 4004, released in 1971.
The Intel 4004 was designed and realized by Federico Faggin at Intel with his silicon-gate MOS technology,
along with Intel's Marcian Hoff and Stanley Mazor and Busicom's Masatoshi Shima.
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
Computer engineering (CE, CoE, or CpE) is a branch of engineering specialized in developing computer hardware and software.
It integrates several fields of electrical engineering, electronics engineering and computer science.
Computer engi ...
, are considered disciplines in their own right.
Power and energy

Power & Energy engineering deals with the electricity generation, generation, electric power transmission, transmission, and electric power distribution, distribution of electricity as well as the design of a range of related devices. These include
transformer
In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces ...
s, electric generators, electric motors, high voltage engineering, and
power electronics. In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it.
Such systems are called ''on-grid'' power systems and may supply the grid with additional power, draw power from the grid, or do both. Power engineers may also work on systems that do not connect to the grid, called ''off-grid'' power systems, which in some cases are preferable to on-grid systems.
Telecommunications

Telecommunications engineering focuses on the transmission (telecommunications), transmission of information across a communication channel such as a coax cable, optical fiber or free space optical communications, free space. 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. 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 receiver (radio), 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. 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 signal noise, noise, specifically static.
Control engineering

Control engineering focuses on the Mathematical model, modeling of a diverse range of dynamic systems and the design of Controller (control theory), controllers that will cause these systems to behave in the desired manner. 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. 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 Internal combustion engine, motor's Power (physics), power output accordingly. 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.
Electronics

Electronic engineering involves the design and testing of electronic circuits that use the properties of electrical element, components such as resistors, capacitors, inductors, diodes, and transistors to achieve a particular functionality.
The tuned circuit, which allows the user of a radio to electronic filter, 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, radio, commercial radio, and television, early television.
Later, in post-war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers, and microprocessors. In the mid-to-late 1950s, the term ''radio engineering'' gradually gave way to the name ''electronic engineering''.
Before the invention of the integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and electric power, power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed a large number—often millions—of tiny electrical components, mainly transistors, into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.
Microelectronics and nanoelectronics

Microelectronics engineering deals with the design and microfabrication of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as a general electronic component. The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors 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.
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics.
Signal processing

Signal processing deals with the analysis and manipulation of signals. Signals can be either analog signal, analog, in which case the signal varies continuously according to the information, or Digital signal (signal processing), 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 amplifier, amplification and Filter (signal processing), filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the Data compression, compression, error detection and error correction of digitally sampled signals.
Signal processing is a very mathematically oriented and intensive area forming the core of digital signal processing and it is rapidly expanding with new applications in every field of electrical engineering such as communications, control, radar, 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, radios, hi-fi audio equipment, mobile phones, Portable Media Player, 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 Speech synthesis, synthesis, Codec, encoding or decoding digital media, wirelessly Transceiver, transmitting or receiving data, triangulating positions using GPS, and other kinds of image processing, video processing, audio signal processing, audio processing, and speech processing.
Instrumentation

Instrumentation engineering deals with the design of devices to measure physical quantities such as pressure, Volumetric flow rate, flow, and temperature. The design of such instruments requires a good understanding of
physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
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.
Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control.
Computers

Computer engineering deals with the design of computers and computer systems. This may involve the design of new computer hardware, 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. 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. Robots are one of the applications of computer engineering.
Photonics and optics

Photonics and
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...
deals with the generation, transmission, amplification, modulation, detection, and analysis of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
. 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

Mechatronics is an engineering discipline that deals with the convergence of electrical and machine, mechanical systems. Such combined systems are known as
electromechanical
Electromechanics combine processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focus on the interaction of electrical and mechanical systems as a whole and how the two systems interact with each ...
systems and have widespread adoption. Examples include automation, automated manufacturing systems, HVAC, heating, ventilation and air-conditioning systems, and various subsystems of aircraft and automobiles.
''Electronic systems design'' is the subject within electrical engineering that deals with the multi-disciplinary design issues of complex electrical and mechanical systems.
The term ''mechatronics'' is typically used to refer to macroscopic systems but Futures studies, 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, 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.
In aerospace engineering and robotics, an example is the most recent electric propulsion and ion propulsion.
Education

Electrical engineers typically possess an academic degree with a major in electrical engineering, electronics engineering, electrical engineering technology,
or electrical and electronic engineering. 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
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
, mathematics, computer science, project management, and a list of electrical engineering topics, variety of topics in electrical engineering.
Initially such topics cover most, if not all, of the subdisciplines of electrical engineering.

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.
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.
Professional practice
In most countries, a bachelor's degree in engineering represents the first step towards
professional certification
Professional certification, trade certification, or professional designation, often called simply ''certification'' or ''qualification'', is a designation earned by a person to assure qualification to perform a job or task. Not all certifications ...
and the degree program itself is certified by a
professional body
A professional association (also called a professional body, professional organization, or professional society) is a group that usually seeks to advocacy, further a particular profession, the interests of individuals and organisations engaged in ...
.
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 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". This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act. In other countries, no such legislation exists. Practically all certifying bodies maintain a ethical code, code of ethics that they expect all members to abide by or risk expulsion. In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations, such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines.
The IEEE has a corporate office ...
(IEEE) and the
Institution of Engineering and Technology
The Institution of Engineering and Technology (IET) is a multidisciplinary professional engineering institution. The IET was formed in 2006 from two separate institutions: the Institution of Electrical Engineers (IEE), dating back to 1871,Engin ...
(IET). The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually. The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe. Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency. An MIET(Member of the Institution of Engineering and Technology) is recognised in Europe as an Electrical and computer (technology) engineer.
In Australia, Canada, and the United States, electrical engineers make up around 0.25% of the labor force.
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 telecommunications systems, the operation of electric power stations, the lighting and wiring of buildings, the design of household appliances, or the electrical control theory, control of industrial machinery.

Fundamental to the discipline are the sciences of
physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...
and mathematics as these help to obtain both a Qualitative data, qualitative and Quantity, quantitative description of how such systems will work. Today most engineering work involves the use of computers and it is commonplace to use computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.

Although most electrical engineers will understand basic
circuit theory (that is, the interactions of elements such as resistors, capacitors, diodes, transistors, and inductors in a circuit), the theories employed by engineers generally depend upon the work they do. For example, quantum mechanics and solid state physics might be relevant to an engineer working on VLSI (the design of integrated circuits), but are largely irrelevant to engineers working with macroscopic electrical systems. Even
circuit theory may not be relevant to a person designing telecommunications systems that use commercial off-the-shelf, off-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasize numeracy, strong numerical skills, computer literacy, and the ability to understand the technical terminology, technical language and concepts that relate to electrical engineering.

A wide range of instrumentation is used by electrical engineers. For simple control circuits and alarms, a basic multimeter measuring voltage, electric current, current, and electrical resistance, 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 analyzer (electrical), 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. Power transmission engineering also has great safety concerns due to the high voltages used; although
voltmeter
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit.
A ...
s may in principle be similar to their low voltage equivalents, safety and calibration issues make them very different. Many disciplines of electrical engineering use tests specific to their discipline. Audio electronics engineers use audio system measurements, 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 (electronics), noise. Likewise, information technology have their own test sets, often specific to a particular data format, and the same is true of television broadcasting.

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 schedule (project management), project schedules. Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and technical writing, strong written communication skills are therefore very important.
The Office, 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.
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. Conversely, the engineer
Oliver Heaviside
Oliver Heaviside ( ; 18 May 1850 – 3 February 1925) was an English mathematician and physicist who invented a new technique for solving differential equations (equivalent to the Laplace transform), independently developed vector calculus, an ...
produced major work on the mathematics of transmission on telegraph cables. 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.
[Martini, p. 179]
See also
*Barnacle (slang)
*Comparison of EDA software
*Electrical Technologist
*Electronic design automation
*Glossary of electrical and electronics engineering
*Index of electrical engineering articles
*Information engineering
*
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronics, electronic and related technologies. IEC standards cover a va ...
(IEC)
*List of electrical engineers
*List of engineering branches
*List of mechanical, electrical and electronic equipment manufacturing companies by revenue
*List of Russian electrical engineers
*Occupations in electrical/electronics engineering
*Outline of electrical engineering
*Timeline of electrical and electronic engineering
Notes
References
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*Martini, L., "BSCCO-2233 multilayered conductors", in ''Superconducting Materials for High Energy Colliders'', pp. 173–181, World Scientific, 2001 .
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*Schmidt, Rüdiger, "The LHC accelerator and its challenges", in Kramer M.; Soler, F.J.P. (eds), ''Large Hadron Collider Phenomenology'', pp. 217–250, CRC Press, 2004 .
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External links
International Electrotechnical Commission (IEC) in-depth look at Electrical Engineering – online courses with video lectures.
IEEE Global History NetworkA wiki-based site with many resources about the history of IEEE, its members, their professions and electrical and informational technologies and sciences.
{{Authority control
Electrical engineering,
Electronic engineering
Computer engineering
Electrical and computer engineering
Engineering disciplines