engineering
Engineering is the use of scientific method, scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad rang ...
discipline concerned with the study, design, and application of equipment, devices, and systems which use
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
,
electronics
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
, and
electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
. It emerged as an identifiable occupation in the latter half of the 19th century after
commercialization
Commercialization or commercialisation 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 ear ...
of the
electric telegraph
Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
, the telephone, and
electrical power
Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of ...
generation, distribution, and use.
Electrical engineering is now divided into a wide range of different fields, including
computer engineering
Computer engineering (CoE or CpE) is a branch of electrical engineering and computer science that integrates several fields of computer science and electronic engineering required to develop computer hardware and software. Computer engineers ...
,
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 util ...
,
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,
radio-frequency engineering
Radio-frequency (RF) engineering is a subset of electronic engineering involving the application of transmission line, waveguide, antenna and electromagnetic field principles to the design and application of devices that produce or use signals w ...
,
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, and scientific measurements. Signal processing techniq ...
,
instrumentation
Instrumentation a collective term for measuring instruments that are used for indicating, measuring and recording physical quantities. The term has its origins in the art and science of scientific instrument-making.
Instrumentation can refer to ...
,
photovoltaic cell
A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physics, physical and Chemical substance, chemical phenomenon.electronics
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
, 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 instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
and
photonics
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Though ...
. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering,
power electronics
Power electronics is the application of electronics to the control and conversion of electric power.
The first high-power electronic devices were made using mercury-arc valves. In modern systems, the conversion is performed with semiconducto ...
, electromagnetics and waves,
microwave engineering
Microwave engineering pertains to the study and design of microwave circuits, components, and systems. Fundamental principles are applied to analysis, design and measurement techniques in this field. The short wavelengths involved distinguish this ...
,
nanotechnology
Nanotechnology, also shortened to nanotech, is the use of matter on an atomic, molecular, and supramolecular scale for industrial purposes. The earliest, widespread description of nanotechnology referred to the particular technological goal o ...
,
electrochemistry
Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outco ...
, renewable energies, mechatronics/control, and electrical materials science.
Electrical engineers typically hold a
degree
Degree may refer to:
As a unit of measurement
* Degree (angle), a unit of angle measurement
** Degree of geographical latitude
** Degree of geographical longitude
* Degree symbol (°), a notation used in science, engineering, and mathematics
...
in electrical engineering or electronic engineering. Practising 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) usually seeks to further a particular profession, the interests of individuals and organisations engaged in that profession, and the ...
or an international standards organization. These include the
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
(IEC), the
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
(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, and ...
(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
Circuit may refer to:
Science and technology
Electrical engineering
* Electrical circuit, a complete electrical network with a closed-loop giving a return path for current
** Analog circuit, uses continuous signal levels
** Balanced circui ...
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 planning, procurement and execution of a project, in any undertaking that has a defined scope, defined start and a defined f ...
. 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.
Ana ...
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 are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...
and
static electricity
Static electricity is an imbalance of electric charges within or on the surface of a material or between materials. The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is na ...
. He is credited with establishing the term "electricity". He also designed the
versorium The versorium (Latin word for "turn around") was the first electroscope, the first instrument that could detect the presence of static electric charge. It was invented in 1600 by William Gilbert, physician to Queen Elizabeth I.
Description
Th ...
: a device that detects the presence of statically charged objects. In 1762 Swedish professor
Johan Wilcke
Johan Carl Wilcke was a Swedish physicist.
Biography
Wilcke was born in Wismar, son of a clergyman who in 1739 was appointed second pastor of the German Church in Stockholm. He went to the German school in Stockholm and enrolled at the Univers ...
invented a device later named
electrophorus
In electromagnetism, an electrophorus or electrophore is a simple, manual, capacitive, electrostatic generator used to produce charge via the process of electrostatic induction. A first version of it was invented in 1762 by Swedish professor Jo ...
that produced a static electric charge. By 1800
Alessandro Volta
Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist and lay Catholic who was a pioneer of electricity and power who is credited as the inventor of the electric battery and the ...
had developed the
voltaic pile
upright=1.2, Schematic diagram of a copper–zinc voltaic pile. The copper and zinc discs were separated by cardboard or felt spacers soaked in salt water (the electrolyte). Volta's original piles contained an additional zinc disk at the bottom, ...
, 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 ( , ; often rendered Oersted in English; 14 August 17779 March 1851) was a Danish physicist and chemist who discovered that electric currents create magnetic fields, which was the first connection found between electricity ...
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 physicist and inventor who made the first electromagnets, and invented the first practical British electric motor.
Early life
Sturgeon was born on 22 May 1783 in Whittington, ...
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 wound into a coil. A current through the wire creates a magnetic field which is concentrated in the ...
, of
Joseph Henry
Joseph Henry (December 17, 1797– May 13, 1878) was an American scientist 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 of the Smith ...
and
Edward Davy
Edward Davy (16 June 1806 – 26 January 1885) was an English physician, scientist, and inventor who played a prominent role in the development of telegraphy, and invented an electric relay.
Davy was born in Ottery St Mary, Devonshire, England, ...
who invented the
electrical relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
in 1835, of
Georg Ohm
Georg Simon Ohm (, ; 16 March 1789 – 6 July 1854) was a German physicist and mathematician. 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 stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving pa ...
and
potential difference
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
Michael Faraday
Michael Faraday (; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. 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 (emf) across an electrical conductor in a changing magnetic field.
Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk ...
in 1831), and of
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and ligh ...
, who in 1873 published a unified
theory
A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be s ...
of electricity and
magnetism
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...
in his treatise ''Electricity and Magnetism''.
In 1782,
Georges-Louis Le Sage
Georges-Louis Le Sage (; 13 June 1724 – 9 November 1803) was a Genevan physicist and is most known for his theory of gravitation, for his invention of an electric telegraph and his anticipation of the kinetic theory of gases. Furthermore, he ...
developed and presented in
Berlin
Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constitue ...
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
Francisco Salva Campillo (Catalan: Francesc Salvà i Campillo, July 12, 1751 – February 13, 1828) was a Spanish Catalan prominent late-Enlightenment period scientist known for working as a physician, physicist, meteorologist.
Early life and e ...
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 – Alessandro Volta's electric battery for generating an electric current and William Nicholson and Anthony Carlyle's electrolysis of water.
Electrical telegraph
Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
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 telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
network, and the first professional electrical engineering institutions were founded in the UK and USA to support the new discipline.
Francis Ronalds
Sir Francis Ronalds FRS (21 February 17888 August 1873) was an English scientist and inventor, and arguably the first electrical engineer. He was knighted for creating the first working electric telegraph over a substantial distance. In 1816 ...
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 Te ...
) 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 cable Submarine cable is any electrical cable that is laid on the seabed, although the term is often extended to encompass cables laid on the bottom of large freshwater bodies of water.
Examples include:
*Submarine communications cable
*Submarine power ...
s, and, from about 1890,
wireless telegraphy
Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental technologies for ...
.
Practical applications and advances in such fields created an increasing need for standardised
units of measure
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multi ...
. They led to the international standardization of the units
volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827).
Defi ...
,
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 elect ...
,
coulomb
The coulomb (symbol: C) is the unit of electric charge in the International System of Units (SI).
In the present version of the SI it is equal to the electric charge delivered by a 1 ampere constant current in 1 second and to elementary char ...
,
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 (b ...
,
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 (SI). It is named after the English physicist Michael Faraday (1791–1867). In SI base unit ...
, and
henry
Henry may refer to:
People
*Henry (given name)
* Henry (surname)
* Henry Lau, Canadian singer and musician who performs under the mononym Henry
Royalty
* Portuguese royalty
** King-Cardinal Henry, King of Portugal
** Henry, Count of Portugal, ...
. This was achieved at an international conference in Chicago in 1893. 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.
During these years, the study of electricity was largely considered to be a subfield of
physics
Physics is the natural science that studies matter, its 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 which r ...
since the early electrical technology was considered
electromechanical
In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
in nature. The
Technische Universität Darmstadt
The Technische Universität Darmstadt (official English name Technical University of Darmstadt, sometimes also referred to as Darmstadt University of Technology), commonly known as TU Darmstadt, is a research university in the city of 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 land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
(MIT) in the physics department under Professor Charles Cross, though it was
Cornell University
Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to teach an ...
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
Andrew Dickson White (November 7, 1832 – November 4, 1918) was an American historian and educator who cofounded Cornell University and served as its first president for nearly two decades. He was known for expanding the scope of college curricu ...
established the first Department of Electrical Engineering in the United States. In the same year,
University College London
, mottoeng = Let all come who by merit deserve the most reward
, established =
, type = Public research university
, endowment = £143 million (2020)
, budget = ...
founded the first chair of electrical engineering in Great Britain. Professor Mendell P. Weinbach at
University of Missouri
The University of Missouri (Mizzou, MU, or Missouri) is a public university, public Land-grant university, land-grant research university in Columbia, Missouri. It is Missouri's largest university and the flagship of the four-campus Universit ...
established the electrical engineering department in 1886. Afterwards, universities and
institutes of technology
An institute of technology (also referred to as: technological university, technical university, university of technology, technological educational institute, technical college, polytechnic university or just polytechnic) is an institution of te ...
gradually started to offer electrical engineering programs to their students all over the world.
During these decades use of electrical engineering increased dramatically. In 1882,
Thomas Edison
Thomas Alva Edison (February 11, 1847October 18, 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 inventio ...
switched on the world's first large-scale electric power network that provided 110 volts —
direct current
Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...
(DC) — to 59 customers on
Manhattan Island
Manhattan (), known regionally as the City, is the most densely populated and geographically smallest of the five boroughs of New York City. The borough is also coextensive with New York County, one of the original counties of the U.S. state ...
in New York City. In 1884,
Sir Charles Parsons
Sir Charles Algernon Parsons, (13 June 1854 – 11 February 1931) was an Anglo-Irish engineer, best known for his invention of the compound steam turbine, and as the eponym of C. A. Parsons and Company. He worked as an engineer on ...
invented the
steam turbine
A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turbin ...
allowing for more efficient electric power generation.
Alternating current
Alternating current (AC) is an electric current which 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 whic ...
, with its ability to transmit power more efficiently over long distances via the use of
transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
s, developed rapidly in the 1880s and 1890s with transformer designs by
Károly Zipernowsky
Károly Zipernowsky (born as Carl Zipernowsky, 4 April 1853 in Vienna – 29 November 1942 in Budapest) was an Austrian-born Hungarian electrical engineer. He invented the transformer with his colleagues (Miksa Déri and Ottó Bláthy) at t ...
,
Ottó Bláthy
Ottó Titusz Bláthy (11 August 1860 – 26 September 1939) was a Hungarian electrical engineer. In his career, he became the co-inventor of the modern electric transformer, the tension regulator, the AC watt-hour meter. motor capacitor f ...
and
Miksa Déri
Miksa Déri (27 October 1854 November, Bács, Kingdom of Hungary, (now: Bač, Serbia) – 3 March 1938) was a Hungarian electrical engineer, inventor, power plant builder. He contributed with his partners Károly Zipernowsky and Ottó Bláth ...
(later called ZBD transformers),
Lucien Gaulard
Lucien Gaulard (16 July 1850 – 26 November 1888) invented devices for the Electricity distribution, transmission of alternating current electrical energy.
Biography
Gaulard was born in Paris, France in 1850.
A power transformer developed by Ga ...
,
John Dixon Gibbs
John Dixon Gibbs (1834–1912) was a British engineer and financier who, together with Lucien Gaulard, is often credited as the co-inventor of the AC step-down transformer. The transformer was first demonstrated in 1883 at London's Royal Aquarium ...
and
William Stanley, Jr.
William Stanley Jr. (November 28, 1858 – May 14, 1916) was an American physicist born in Brooklyn, New York. During his career, he obtained 129 patents covering a variety of electric devices. In 1913, he also patented an all-steel vacuum bottl ...
Practical
AC motor
An AC motor is an electric motor driven by an alternating current (AC). The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor ...
designs including
induction motor
An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction mot ...
s 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 ...
three-phase
Three-phase electric power (abbreviated 3φ) is a common type of alternating current used in electricity generation, Electric power transmission, transmission, and Electric power distribution, distribution. It is a type of polyphase system empl ...
form by
Mikhail Dolivo-Dobrovolsky
Mikhail Osipovich Dolivo-Dobrovolsky (russian: Михаи́л О́сипович Доли́во-Доброво́льский; german: Michail von Dolivo-Dobrowolsky or ''Michail Ossipowitsch Doliwo-Dobrowolski''; – ) was a Russian Empire ...
and
Charles Eugene Lancelot Brown
Brown c. 1900
Charles Eugene Lancelot Brown (17 June 1863 – 2 May 1924) was a Swiss businessman and engineer who co-founded Brown, Boveri & Cie (BBC), which later became ASEA Brown Boveri.
Biography
Brown was born on 17 June 1863 in Winterth ...
.
Charles Steinmetz
Charles Proteus Steinmetz (born Karl August Rudolph Steinmetz, April 9, 1865 – October 26, 1923) was a German-born American mathematician and electrical engineer and professor at Union College. He fostered the development of alternating ...
and
Oliver Heaviside
Oliver Heaviside FRS (; 18 May 1850 – 3 February 1925) was an English self-taught mathematician and physicist who invented a new technique for solving differential equations (equivalent to the Laplace transform), independently developed vec ...
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
The war of the currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s. It grew out of two lighting systems developed in the late 1870s and early 1880s; arc ...
'' between a
George Westinghouse
George Westinghouse Jr. (October 6, 1846 – March 12, 1914) was an American entrepreneur and engineer based in Pennsylvania who created the railway air brake and was a pioneer of the electrical industry, receiving his first patent at the age of ...
backed AC system and a Thomas Edison backed DC power system, with AC being adopted as the overall standard.
radio technology
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
and electronics. The mathematical work of
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and ligh ...
during the 1850s had shown the relationship of different forms of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, inf ...
including the possibility of invisible airborne waves (later called "radio waves"). In his classic physics experiments of 1888,
Heinrich Hertz
Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's Maxwell's equations, equations of electrom ...
proved Maxwell's theory by transmitting
radio wave
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (short ...
s with a
spark-gap transmitter
A spark-gap transmitter is an obsolete type of radio transmitter which generates radio waves by means of an electric spark."Radio Transmitters, Early" in Spark-gap transmitters were the first type of radio transmitter, and were the main type use ...
, 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
Guglielmo Giovanni Maria Marconi, 1st Marquis of Marconi (; 25 April 187420 July 1937) was an Italians, Italian inventor and electrical engineering, electrical engineer, known for his creation of a practical radio wave-based Wireless telegrap ...
began work on a way to adapt the known methods of transmitting and detecting these "Hertzian waves" into a purpose built commercial wireless telegraphic system. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of .
Millimetre wave
file:EM Spectrum Properties edit.svg, 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter.
The millimetre (American and British Eng ...
communication was first investigated by
Jagadish Chandra Bose
Sir Jagadish Chandra Bose
(;, ; 30 November 1858 – 23 November 1937) was a biologist, physicist, Botany, botanist and an early writer of science fiction. He was a pioneer in the investigation of radio microwave optics, made significant contr ...
during 18941896, when he reached an
extremely high frequency
Extremely high frequency (EHF) is the International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the ...
of up to 60
GHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
in his experiments. He also introduced the use of
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
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
A crystal detector is an obsolete electronic component used in some early 20th century radio receivers that consists of a piece of crystalline mineral which rectifies the alternating current radio signal. It was employed as a detector (demod ...
in 1901.
In 1897,
Karl Ferdinand Braun
Karl Ferdinand Braun (; 6 June 1850 – 20 April 1918) was a German electrical engineer, inventor, physicist and Nobel laureate in physics. Braun contributed significantly to the development of radio and television technology: he shared the ...
introduced the
cathode ray tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms ( oscilloscope), pictu ...
as part of an
oscilloscope
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetiti ...
, a crucial enabling technology for
electronic television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, e ...
diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
A diode ...
, in 1904. Two years later,
Robert von Lieben
Robert von Lieben (September 5, 1878, in Vienna – February 20, 1913, in Vienna) was an Austrian entrepreneur, and self-taught physicist and inventor. Lieben and his associates Eugen Reisz and Siegmund Strauss invented and produced a gas ...
and
Lee De Forest
Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor and a fundamentally important early pioneer in electronics. He invented the first electronic device for controlling current flow; the three-element "Audion" triode va ...
independently developed the amplifier tube, called the
triode
A triode is an electronic amplifying vacuum tube (or ''valve'' in British English) consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 19 ...
.
In 1920,
Albert Hull
Albert Wallace Hull (19 April 1880 – 22 January 1966) was an American physicist and electrical engineer who made contributions to the development of vacuum tubes, and invented the magnetron. He was a member of the National Academy of Scienc ...
developed the
magnetron
The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field while ...
which would eventually lead to the development of the
microwave oven
A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce t ...
in 1946 by
Percy Spencer
Percy Lebaron Spencer (July 19, 1894 – September 8, 1970) was an American physicist and inventor. He became known as the inventor of the microwave oven.
Early life
Spencer was born in Howland, Maine. Eighteen months later, Spencer's father ...
. In 1934, the British military began to make strides toward
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
(which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at
Bawdsey
Bawdsey is a village and civil parish in Suffolk, eastern England. Located on the other side of the river Deben from Felixstowe, it had an estimated population of 340 in 2007, reducing to 276 at the Census 2011.
Bawdsey Manor is notable as the ...
in August 1936.
In 1941,
Konrad Zuse
Konrad Ernst Otto Zuse (; 22 June 1910 – 18 December 1995) was a German civil engineer, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program-c ...
presented the Z3, the world's first fully functional and programmable computer using electromechanical parts. In 1943,
Tommy Flowers
Thomas Harold Flowers MBE (22 December 1905 – 28 October 1998) was an English engineer with the British General Post Office. During World War II, Flowers designed and built Colossus, the world's first programmable electronic computer, to help ...
designed and built the
Colossus
Colossus, Colossos, or the plural Colossi or Colossuses, may refer to:
Statues
* Any exceptionally large statue
** List of tallest statues
** :Colossal statues
* ''Colossus of Barletta'', a bronze statue of an unidentified Roman emperor
* ''Col ...
, the world's first fully functional, electronic, digital and programmable computer. In 1946, the
ENIAC
ENIAC (; Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer, completed in 1945. There were other computers that had these features, but the ENIAC had all of them in one packa ...
(Electronic Numerical Integrator and Computer) of
John Presper Eckert
John Adam Presper Eckert Jr. (April 9, 1919 – June 3, 1995) was an American electrical engineer and computer pioneer. With John Mauchly, he designed the first general-purpose electronic digital computer (ENIAC), presented the first course in co ...
and
John Mauchly
John William Mauchly (August 30, 1907 – January 8, 1980) was an American physicist who, along with J. Presper Eckert, designed ENIAC, the first general-purpose electronic digital computer, as well as EDVAC, BINAC and UNIVAC I, the first co ...
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
Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American people, American mathematician, electrical engineering, electrical engineer, and cryptography, cryptographer known as a "father of information theory".
As a 21-year-o ...
publishes "A Mathematical Theory of Communication" which mathematically describes the passage of information with uncertainty (
electrical noise
In electronics, noise is an unwanted disturbance in an electrical signal.
Noise generated by electronic devices varies greatly as it is produced by several different effects.
In particular, noise is inherent in physics, and central to the ...
).
Solid-state electronics
The first working
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
was a
point-contact transistor
The point-contact transistor was the first type of transistor to be successfully demonstrated. It was developed by research scientists John Bardeen and Walter Brattain at Bell Laboratories in December 1947. They worked in a group led by physicis ...
invented by
John Bardeen
John Bardeen (; May 23, 1908 – January 30, 1991) was an American physicist and engineer. He is the only person to be awarded the Nobel Prize in Physics twice: first in 1956 with William Shockley and Walter Brattain for the invention of the tran ...
and
Walter Houser Brattain
Walter Houser Brattain (; February 10, 1902 – October 13, 1987) was an American physicist at Bell Labs who, along with fellow scientists John Bardeen and William Shockley, invented the point-contact transistor in December 1947. They shared t ...
while working under
William Shockley
William Bradford Shockley Jr. (February 13, 1910 – August 12, 1989) was an American physicist and inventor. He was the manager of a research group at Bell Labs that included John Bardeen and Walter Brattain. The three scientists were jointly ...
at the
Bell Telephone Laboratories
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial research and scientific development company owned by mul ...
(BTL) in 1947. They then invented the
bipolar junction transistor
A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar ...
in 1948. While early
junction transistor
A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar ...
s were relatively bulky devices that were difficult to manufacture on a
mass-production
Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized products in a constant flow, including and especially on assembly lines. Together with job production and bat ...
basis, they opened the door for more compact devices.
The first
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s were the
hybrid integrated circuit
A hybrid integrated circuit (HIC), hybrid microcircuit, hybrid circuit or simply hybrid is a miniaturized electronic circuit constructed of individual devices, such as semiconductor devices (e.g. transistors, diodes or monolithic ICs) and pa ...
invented by
Jack Kilby
Jack St. Clair Kilby (November 8, 1923 – June 20, 2005) was an American electrical engineer who took part (along with Robert Noyce of Fairchild) in the realization of the first integrated circuit while working at Texas Instruments (TI) in 1 ...
at
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
in 1958 and the monolithic integrated circuit chip invented by
Robert Noyce
Robert Norton Noyce (December 12, 1927 – June 3, 1990), nicknamed "the Mayor of Silicon Valley", was an American physicist and entrepreneur who co-founded Fairchild Semiconductor in 1957 and Intel Corporation in 1968. He is also credited wit ...
at
Fairchild Semiconductor
Fairchild Semiconductor International, Inc. was an American semiconductor company based in San Jose, California. Founded in 1957 as a division of Fairchild Camera and Instrument, it became a pioneer in the manufacturing of transistors and of int ...
in 1959.
The
MOSFET
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which d ...
(metal-oxide-semiconductor field-effect transistor, or MOS transistor) was invented by
Mohamed Atalla
Mohamed M. Atalla ( ar, محمد عطاالله; August 4, 1924 – December 30, 2009) was an Egyptian-American engineer, physicist, cryptographer, inventor and entrepreneur. He was a semiconductor pioneer who made important contributions to ...
and
Dawon Kahng
Dawon Kahng ( ko, 강대원; May 4, 1931 – May 13, 1992) was a Korean-American electrical engineer and inventor, known for his work in solid-state electronics. He is best known for inventing the MOSFET (metal–oxide–semiconductor field-effe ...
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
The electronics industry is the economic sector that produces electronic devices. It emerged in the 20th century and is today one of the largest global industries. Contemporary society uses a vast array of electronic devices built-in automated or ...
, becoming the most widely used electronic device in the world.
The MOSFET made it possible to build 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
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
in 1962. MOS technology enabled
Moore's law
Moore's law is the observation that the number of transistors in a dense integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empir ...
Gordon Moore
Gordon Earle Moore (born January 3, 1929) is an American businessman, engineer, and the co-founder and chairman emeritus of Intel Corporation. He is also the original proponent of Moore's law.
As of March 2021, Moore's net worth is rep ...
in 1965.
Silicon-gate
In Semiconductor device fabrication, semiconductor electronics fabrication technology, a self-aligned gate is a transistor manufacturing approach whereby the gate (transistor), gate electrode of a MOSFET (metal–oxide–semiconductor field-effec ...
MOS technology was developed by
Federico Faggin
Federico Faggin (, ; born 1 December 1941) is an Italian physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group du ...
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
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which d ...
miniaturization at an exponential pace (as predicted by
Moore's law
Moore's law is the observation that the number of transistors in a dense integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empir ...
Apollo 11
Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, an ...
in 1969 was enabled by
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
's adoption of advances in
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
electronic technology
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification a ...
, including MOSFETs in the
Interplanetary Monitoring Platform Interplanetary Monitoring Platform was a program managed by the NASA Goddard Space Flight Center in Greenbelt, Maryland, as part of the Explorers program, with the primary objectives of investigation of interplanetary plasma and the interplaneta ...
(IMP) and silicon integrated circuit chips in the
Apollo Guidance Computer
The Apollo Guidance Computer (AGC) was a digital computer produced for the Apollo program that was installed on board each Apollo command module (CM) and Apollo Lunar Module (LM). The AGC provided computation and electronic interfaces for guidan ...
(AGC).
The development of MOS integrated circuit technology in the 1960s led to the invention of the
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
in the early 1970s. The first single-chip microprocessor was the
Intel 4004
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs.
The 4004 was the first signific ...
, 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
Marcian Edward "Ted" Hoff Jr. (born October 28, 1937 in Rochester, New York) is one of the inventors of the microprocessor.
Education and work history
Hoff received a bachelor's degree in electrical engineering from the Rensselaer Polytechnic Inst ...
and
Stanley Mazor
Stanley Mazor is an American microelectronics engineer who was born on 22 October 1941 in Chicago, Illinois. He is one of the co-inventors of the world's first microprocessor architecture, the Intel 4004, together with Ted Hoff, Masatoshi Shima ...
and Busicom's Masatoshi Shima. The microprocessor led to the development of
microcomputer
A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PC ...
s and personal computers, and the
microcomputer revolution
The history of the personal computer as a mass-market consumer electronic device began with the microcomputer revolution of the 1970s. A personal computer is one intended for interactive individual use, as opposed to a mainframe computer where ...
.
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
Electronics engineering is a sub-discipline of electrical engineering which emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current ...
and
computer engineering
Computer engineering (CoE or CpE) is a branch of electrical engineering and computer science that integrates several fields of computer science and electronic engineering required to develop computer hardware and software. Computer engineers ...
, are considered disciplines in their own right.
Power and energy
Power & Energy engineering deals with the
generation
A generation refers to all of the people born and living at about the same time, regarded collectively. It can also be described as, "the average period, generally considered to be about 20–30 years, during which children are born and gr ...
,
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
, and
distribution Distribution may refer to:
Mathematics
*Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations
* Probability distribution, the probability of a particular value or value range of a vari ...
of electricity as well as the design of a range of related devices. These include
transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
s,
electric generator
In electricity generation, a generator is a device that converts motive power (mechanical energy) or fuel-based power (chemical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas ...
s,
electric motor
An electric motor is an Electric machine, electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a Electromagneti ...
s, high voltage engineering, and
power electronics
Power electronics is the application of electronics to the control and conversion of electric power.
The first high-power electronic devices were made using mercury-arc valves. In modern systems, the conversion is performed with semiconducto ...
. In many regions of the world, governments maintain an electrical network called a
power grid
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...
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. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.
Telecommunications
Telecommunications engineering focuses on the
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
of information across a
communication channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for informa ...
such as a
coax cable
Coaxial cable, or coax (pronounced ) is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ( insulating material); many coaxial cables also have a p ...
,
optical fiber
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...
or
free space
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
. Transmissions across free space require information to be encoded in a
carrier signal
In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a ...
to shift the information to a carrier frequency suitable for transmission; this is known as
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
. Popular analog modulation techniques include
amplitude modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...
and
frequency modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280. ...
. 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
transmitter
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna (radio), antenna. The transmitter itself generates a radio frequency alternating current, which i ...
s and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a
transceiver
In radio communication, a transceiver is an electronic device which is a combination of a radio ''trans''mitter and a re''ceiver'', hence the name. It can both transmit and receive radio waves using an antenna, for communication purposes. The ...
. A key consideration in the design of transmitters is their
power consumption
Electric energy consumption is the form of energy consumption that uses electrical energy. Electric energy consumption is the actual energy demand made on existing electricity supply for transportation, residential, industrial, commercial, and o ...
as this is closely related to their
signal strength
In telecommunications, particularly in radio frequency engineering, signal strength refers to the transmitter power output as received by a reference antenna at a distance from the transmitting antenna. High-powered transmissions, such as those us ...
. 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
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...
, specifically static.
Control engineering
Control engineering
Control engineering or control systems engineering is an engineering discipline that deals with control systems, applying control theory to design equipment and systems with desired behaviors in control environments. The discipline of controls o ...
focuses on the
modeling
A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure.
Models c ...
of a diverse range of
dynamic system
In mathematics, a dynamical system is a system in which a Function (mathematics), function describes the time dependence of a Point (geometry), point in an ambient space. Examples include the mathematical models that describe the swinging of a ...
s and the design of
controller
Controller may refer to:
Occupations
* Controller or financial controller, or in government accounting comptroller, a senior accounting position
* Controller, someone who performs agent handling in espionage
* Air traffic controller, a person ...
s that will cause these systems to behave in the desired manner. To implement such controllers, electronics control engineers may use
electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electrical ...
s,
digital signal processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...
s,
microcontroller
A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...
s, and
programmable logic controller
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity tha ...
s (PLCs).
Control engineering
Control engineering or control systems engineering is an engineering discipline that deals with control systems, applying control theory to design equipment and systems with desired behaviors in control environments. The discipline of controls o ...
has a wide range of applications from the flight and propulsion systems of
commercial airliner
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...
s to the
cruise control
Cruise control (also known as speed control, cruise command, autocruise, or tempomat) is a system that automatically controls the speed of a motor vehicle. The system is a servomechanism that takes over the throttle of the car to maintain a ste ...
present in many modern
automobile
A car or automobile is a motor vehicle with Wheel, wheels. Most definitions of ''cars'' say that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, pe ...
s. It also plays an important role in
industrial automation
Automation describes a wide range of technologies that reduce human intervention in processes, namely by predetermining decision criteria, subprocess relationships, and related actions, as well as embodying those predeterminations in machines ...
.
Control engineers often use
feedback
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...
when designing
control system
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial c ...
s. For example, in an
automobile
A car or automobile is a motor vehicle with Wheel, wheels. Most definitions of ''cars'' say that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, pe ...
with
cruise control
Cruise control (also known as speed control, cruise command, autocruise, or tempomat) is a system that automatically controls the speed of a motor vehicle. The system is a servomechanism that takes over the throttle of the car to maintain a ste ...
the vehicle's
speed
In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...
is continuously monitored and fed back to the system which adjusts the motor's
power
Power most often refers to:
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power
* Power (social and political), the ability to influence people or events
** Abusive power
Power may a ...
output accordingly. Where there is regular feedback,
control theory
Control theory is a field of mathematics that deals with the control of dynamical systems in engineered processes and machines. The objective is to develop a model or algorithm governing the application of system inputs to drive the system to a ...
can be used to determine how the system responds to such feedback.
Control engineers also work in
robotics
Robotics is an interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist humans. Robotics integrat ...
to design autonomous systems using control algorithms which interpret sensory feedback to control actuators that move robots such as
autonomous vehicle
Vehicular automation involves the use of mechatronics, artificial intelligence, and multi-agent systems to assist the operator of a vehicle (car, aircraft, watercraft, or otherwise).Hu, J.; Bhowmick, P.; Lanzon, A.,Group Coordinated Control o ...
s, autonomous drones and others used in a variety of industries.
Electronics
Electronic engineering involves the design and testing of
electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electrical ...
s that use the properties of
component
Circuit Component may refer to:
•Are devices that perform functions when they are connected in a circuit.
In engineering, science, and technology Generic systems
*System components, an entity with discrete structure, such as an assemb ...
s such as
resistor
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...
s,
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
s,
inductor
An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a c ...
s,
diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
A diode ...
s, and
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s to achieve a particular functionality. The
tuned circuit
An LC circuit, also called a resonant circuit, tank circuit, or tuned circuit, is an electric circuit consisting of an inductor, represented by the letter L, and a capacitor, represented by the letter C, connected together. The circuit can ac ...
, which allows the user of a radio to
filter
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
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
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
,
commercial radio
Commercial broadcasting (also called private broadcasting) is the broadcasting of television programs and radio programming by privately owned corporate media, as opposed to state sponsorship. It was the United States′ first model of radio (an ...
, and
early television
Early may refer to:
History
* The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.:
** Early Christianity
** Early modern Europe
Places in the United States
* Early, Iowa
* Early, Texas
* Early ...
. Later, in post-war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers, and
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
s. 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
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and
power
Power most often refers to:
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power
* Power (social and political), the ability to influence people or events
** Abusive power
Power may a ...
and were limited in speed, although they are still common in some applications. By contrast,
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s packed a large number—often millions—of tiny electrical components, mainly
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s, into a small chip around the size of a
coin
A coin is a small, flat (usually depending on the country or value), round piece of metal or plastic used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order t ...
. This allowed for the powerful computers and other electronic devices we see today.
Microelectronics and nanoelectronics
Microelectronics
Microelectronics is a subfield of electronics. As the name suggests, microelectronics relates to the study and manufacture (or microfabrication) of very small electronic designs and components. Usually, but not always, this means micrometre-sc ...
engineering deals with the design and
microfabrication
Microfabrication is the process of fabricating miniature structures of micrometre scales and smaller. Historically, the earliest microfabrication processes were used for integrated circuit fabrication, also known as "semiconductor manufacturing" o ...
of very small electronic circuit components for use in an
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
or sometimes for use on their own as a general electronic component. The most common microelectronic components are
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s, although all main electronic components (
resistor
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...
s,
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
s etc.) can be created at a microscopic level.
Nanoelectronics
Nanoelectronics refers to the use of nanotechnology in electronic components. The term covers a diverse set of devices and materials, with the common characteristic that they are so small that inter-atomic interactions and quantum mechanical pr ...
is the further scaling of devices down to
nanometer
330px, Different lengths as in respect to the molecular scale.
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re ...
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 semiconductor
Semiconductor materials are nominally small band gap insulators. The defining property of a semiconductor material is that it can be compromised by doping it with impurities that alter its electronic properties in a controllable way.
Because of ...
s 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
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
.
Signal processing
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, and scientific measurements. Signal processing techniq ...
deals with the analysis and manipulation of
signal
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
s. Signals can be either
analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
, in which case the signal varies continuously according to the information, or
digital
Digital usually refers to something using discrete digits, often binary digits.
Technology and computing Hardware
*Digital electronics, electronic circuits which operate using digital signals
**Digital camera, which captures and stores digital i ...
, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and
filtering
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
of audio signals for audio equipment or the
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
and
demodulation
Demodulation is extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated ...
of signals for telecommunications. For digital signals, signal processing may involve the
compression
Compression may refer to:
Physical science
*Compression (physics), size reduction due to forces
*Compression member, a structural element such as a column
*Compressibility, susceptibility to compression
* Gas compression
*Compression ratio, of a ...
,
error detection
In information theory and coding theory with applications in computer science and telecommunication, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communi ...
and
error correction
In information theory and coding theory with applications in computer science and telecommunication, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communica ...
of digitally sampled signals.
Signal Processing is a very mathematically oriented and intensive area forming the core of
digital signal processing
Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are ...
and it is rapidly expanding with new applications in every field of electrical engineering such as communications, control, radar,
audio engineer
An audio engineer (also known as a sound engineer or recording engineer) helps to produce a recording or a live performance, balancing and adjusting sound sources using equalization, dynamics processing and audio effects, mixing, reproduction, ...
ing,
broadcast engineering
Broadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential par ...
, power electronics, and
biomedical engineering
Biomedical engineering (BME) or medical engineering is the application of engineering principles and design concepts to medicine and biology for healthcare purposes (e.g., diagnostic or therapeutic). BME is also traditionally logical sciences ...
as many already existing analog systems are replaced with their digital counterparts.
Analog signal processing Analog signal processing is a type of signal processing conducted on continuous analog signals by some analog means (as opposed to the discrete digital signal processing where the signal processing is carried out by a digital process). "Analog" indi ...
is still important in the design of many
control system
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial c ...
s.
DSP processor ICs are found in many types of modern electronic devices, such as digital
television set
A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube, is a device that combines a tuner, display, and loudspeakers, for the purpose of viewing and hearing television broadcasts, or using ...
s, radios, Hi-Fi audio equipment, mobile phones, multimedia players, camcorders and digital cameras, automobile control systems,
noise cancelling
Active noise control (ANC), also known as noise cancellation (NC), or active noise reduction (ANR), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first. The concept was first develop ...
headphones, digital
spectrum analyzer
A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. The input signal that most co ...
s, missile guidance systems,
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
systems, and
telematics
Telematics is an interdisciplinary field encompassing telecommunications, vehicular technologies ( road transport, road safety, etc.), electrical engineering (sensors, instrumentation, wireless communications, etc.), and computer science (multimedi ...
systems. In such products, DSP may be responsible for
noise reduction
Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree. Noise rejection is the ability of a circuit to isolate an und ...
,
speech recognition
Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the m ...
or
synthesis
Synthesis or synthesize may refer to:
Science Chemistry and biochemistry
*Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors
** Organic synthesis, the chemical synthesis of organ ...
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
, and other kinds of
image processing
An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
,
video processing In electronics engineering, video processing is a particular case of signal processing, in particular image processing, which often employs video filters and where the input and output signals are video files or video streams. Video processing tec ...
speech processing
Speech processing is the study of speech signals and the processing methods of signals. The signals are usually processed in a digital representation, so speech processing can be regarded as a special case of digital signal processing, applied t ...
.
Instrumentation
Instrumentation engineering
Instrumentation a collective term for measuring instruments that are used for indicating, measuring and recording physical quantities. The term has its origins in the art and science of scientific instrument-making.
Instrumentation can refer to ...
deals with the design of devices to measure physical quantities such as
pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
, flow, and temperature. The design of such instruments requires a good understanding of
physics
Physics is the natural science that studies matter, its 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 which r ...
that often extends beyond
electromagnetic theory
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
. For example,
flight instrument
Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with data about the flight situation of that aircraft, such as altitude, airspeed, vertical speed, heading and much more other crucial information in fl ...
s measure variables such as
wind speed
In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer.
Wind speed ...
and altitude to enable pilots the control of aircraft analytically. Similarly,
thermocouple
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the ...
s use the
Peltier-Seebeck effect
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when ...
to measure the temperature difference between two points.
Often instrumentation is not used by itself, but instead as the
sensor
A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
s 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 system
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These progr ...
s. This may involve the design of new hardware. Computer engineers may also work on a system's software. However, the design of complex software systems is often the domain of software engineering, which is usually considered a separate discipline.
Desktop computer
A desktop computer (often abbreviated desktop) is a personal computer designed for regular use at a single location on or near a desk due to its size and power requirements. The most common configuration has a case that houses the power supply ...
s 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 device
An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...
s including
video game console
A video game console is an electronic device that Input/output, outputs a video signal or image to display a video game that can be played with a game controller. These may be home video game console, home consoles, which are generally placed i ...
s and
DVD player
A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to wa ...
s. Computer engineers are involved in many hardware and software aspects of computing.
Robot
A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be c ...
s are one of the applications of computer engineering.
Photonics and optics
Photonics
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Though ...
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 instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
deals with the generation, transmission, amplification, modulation, detection, and analysis of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, inf ...
. The application of optics deals with design of optical instruments such as
lens
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
es,
microscope
A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
s,
telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
s, and other equipment that uses the properties of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, inf ...
. Other prominent applications of optics include
electro-optical sensor
Electro-optical sensors are electronic detectors that convert light, or a change in light, into an electronic signal. These sensors are able to detect electromagnetic radiation from the infrared up to the ultraviolet wavelengths. They are used in ...
s and measurement systems,
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
s,
fiber optic communication
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light is a form of carrier wave that is modulated to carry information. Fiber is pre ...
systems, and optical disc systems (e.g. CD and DVD). Photonics builds heavily on optical technology, supplemented with modern developments such as
optoelectronics
Optoelectronics (or optronics) is the study and application of electronic devices and systems that find, detect and control light, usually considered a sub-field of photonics. In this context, ''light'' often includes invisible forms of radiatio ...
(mostly involving
semiconductor
A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...
s), laser systems,
optical amplifier
An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback fr ...
s and novel materials (e.g.
metamaterial
A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
s).
Related disciplines
Mechatronics
Mechatronics engineering also called mechatronics, is an interdisciplinary branch of engineering that focuses on the integration of mechanical, electrical and electronic engineering systems, and also includes a combination of robotics, electronics, ...
is an engineering discipline which deals with the convergence of electrical and
mechanical
Mechanical may refer to:
Machine
* Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement
* Mechanical calculator, a device used to perform the basic operations of ...
systems. Such combined systems are known as
electromechanical
In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
automobile
A car or automobile is a motor vehicle with Wheel, wheels. Most definitions of ''cars'' say that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, pe ...
s.
''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
The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic.
Overview
When applied to physical phenomena an ...
systems but
futurist
Futurists (also known as futurologists, prospectivists, foresight practitioners and horizon scanners) are people whose specialty or interest is futurology or the attempt to systematically explore predictions and possibilities abou ...
s have predicted the emergence of very small electromechanical devices. Already, such small devices, known as
Microelectromechanical system
Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...
s (MEMS), are used in automobiles to tell
airbag
An airbag is a vehicle occupant-restraint system using a bag designed to inflate extremely quickly, then quickly deflate during a collision. It consists of the airbag cushion, a flexible fabric bag, an inflation module, and an impact sensor. Th ...
s when to deploy, in
digital projector
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. Video projectors use a very bright ultra-high-performance lamp (a special mercury arc lamp), X ...
s to create sharper images, and in
inkjet printer
Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensi ...
s 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
Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date b ...
.
In
Aerospace engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is si ...
and
robotics
Robotics is an interdisciplinary branch of computer science and engineering. Robotics involves design, construction, operation, and use of robots. The goal of robotics is to design machines that can help and assist humans. Robotics integrat ...
, an example is the most recent
electric propulsion
Spacecraft electric propulsion (or just electric propulsion) is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generate thrust to modify the velocity of a sp ...
and ion propulsion.
Education
Electrical engineers typically possess an
academic degree
An academic degree is a qualification awarded to students upon successful completion of a course of study in higher education, usually at a college or university. These institutions commonly offer degrees at various levels, usually including unde ...
with a major in electrical engineering,
electronics engineering
Electronics engineering is a sub-discipline of electrical engineering which emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current f ...
,
electrical engineering technology
Electrical/Electronics engineering technology (EET) is an engineering technology field that implements and applies the principles of electrical engineering. Like electrical engineering, EET deals with the "design, application, installation, manuf ...
, 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
A Bachelor of Engineering (BEng) or a Bachelor of Science in Engineering (BSE) is an academic undergraduate degree awarded to a student after three to five years of studying engineering at an accredited college or university.
In the UK, a Bache ...
, Bachelor of Science,
Bachelor of Technology
A Bachelor of Technology (Latin ''Baccalaureus Technologiae'', commonly abbreviated as B.Tech. or BTech; with honours as B.Tech. (Hons.)) is an undergraduate academic degree conferred after the completion of a three to five-year program of studi ...
, or
Bachelor of Applied Science
The Bachelor of Applied Science, often abbreviated as B.AS., BAS, BSAS, BASc, B.A.Sc., or BAppSc, is an undergraduate degree. There are also ''Bachelor of Arts and Science'' and ''Bachelor of Administration Science'' undergraduate degrees, also a ...
, depending on the university. The
bachelor's degree
A bachelor's degree (from Middle Latin ''baccalaureus'') or baccalaureate (from Modern Latin ''baccalaureatus'') is an undergraduate academic degree awarded by colleges and universities upon completion of a course of study lasting three to six ...
generally includes units covering
physics
Physics is the natural science that studies matter, its 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 which r ...
, mathematics,
computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...
,
project management
Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. Th ...
, and a variety of topics in electrical engineering. Initially such topics cover most, if not all, of the subdisciplines of electrical engineering. At some schools, the students can then choose to emphasize one or more subdisciplines towards the end of their courses of study.
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
A Master of Engineering (abbreviated MEng, M.E. or M.Eng.) is either an academic or professional master's degree in the field of engineering.
International variations
Australia
In Australia, the Master of Engineering degree is a research deg ...
/Master of Science (MEng/MSc), a Master of
Engineering Management
Engineering management is the application of the practice of management to the practice of engineering.
Engineering management is a career that brings together the technological problem-solving ability of engineering and the organizational, admini ...
, a Doctor of Philosophy (PhD) in Engineering, an
Engineering Doctorate
Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specializ ...
(Eng.D.), or an
Engineer's degree
An engineer's degree is an advanced academic degree in engineering which is conferred in Europe, some countries of Latin America, North Africa and a few institutions in the United States. The degree may require a thesis but always requires a non-a ...
. The master's and engineer's degrees may consist of either research,
coursework
Coursework (also course work, especially British English) is work performed by students or trainees for the purpose of learning. Coursework may be specified and assigned by teachers, or by learning guides in self-taught courses. Coursework can e ...
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
An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary education, secondary or tertiary education, tertiary higher education, higher learning (and generally also research or honorary membershi ...
. 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) usually seeks to further a particular profession, the interests of individuals and organisations engaged in that profession, and the ...
. 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
Regulation and licensure in engineering is established by various jurisdictions of the world to encourage life, public welfare, safety, well-being, then environment and other interests of the general public and to define the licensure process thro ...
(in the United States, Canada and South Africa),
Chartered engineer
Regulation and licensure in engineering is established by various jurisdictions of the world to encourage life, public welfare, safety, well-being, then environment and other interests of the general public and to define the licensure process thro ...
or
Incorporated Engineer
An engineering technologist is a professional trained in certain aspects of development and implementation of a respective area of technology. Engineering technology education is even more applied and less theoretical than engineering education ...
(in India, Pakistan, the United Kingdom, Ireland and
Zimbabwe
Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...
), Chartered Professional Engineer (in Australia and New Zealand) or
European Engineer
European Engineer (EUR ING) is an international professional qualification and title for highly qualified engineers used in over 32 European countries. Contemporary EUR ING engineers are degree-qualified and have gained the highest level of profes ...
(in much of the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
).
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
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
's Engineers Act. In other countries, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion. 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
A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tran ...
. In cases where an engineer's work fails he or she may be subject to the negligence, 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 a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
(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, and ...
(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 electricity generation, electric power generation, electrical engineers have contributed to the development of a wide range of technologies. They design, develop, test, and supervise the deployment of electrical systems and electronic devices. For example, they may work on the design of telecommunication systems, the operation of power station, electric power stations, the lighting and electrical wiring, wiring of buildings, the design of home appliance, household appliances, or the electrical control theory, control of industrial machinery.
Fundamental to the discipline are the sciences of
physics
Physics is the natural science that studies matter, its 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 which r ...
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
Circuit may refer to:
Science and technology
Electrical engineering
* Electrical circuit, a complete electrical network with a closed-loop giving a return path for current
** Analog circuit, uses continuous signal levels
** Balanced circui ...
(that is the interactions of elements such as
resistor
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...
s,
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
s,
diode
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
A diode ...
s,
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s, and
inductor
An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a c ...
s in a circuit), the theories employed by engineers generally depend upon the work they do. For example,
quantum mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...
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
Circuit may refer to:
Science and technology
Electrical engineering
* Electrical circuit, a complete electrical network with a closed-loop giving a return path for current
** Analog circuit, uses continuous signal levels
** Balanced circui ...
may not be relevant to a person designing telecommunication 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
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetiti ...
is also an ubiquitous instrument. In RF engineering and high frequency telecommunications,
spectrum analyzer
A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. The input signal that most co ...
s 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.
Ana ...
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
Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. Th ...
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 FRS (; 18 May 1850 – 3 February 1925) was an English self-taught mathematician and physicist who invented a new technique for solving differential equations (equivalent to the Laplace transform), independently developed vec ...
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)
*Electrical Technologist
*Electronic design automation
*Glossary of electrical and electronics engineering
*Index of electrical engineering articles
*Information engineering (field), Information engineering
*
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
(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
;Bibliography
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*Martini, L., "BSCCO-2233 multilayered conductors", in ''Superconducting Materials for High Energy Colliders'', pp. 173–181, World Scientific, 2001 .
*
*
*
*
*
*
*
*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 .
*
*
*
*
*
*
*
*
*
*
*
*
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
International Electrotechnical Commission (IEC) in-depth look at Electrical Engineering – online courses with video lectures. 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.
{{Authority control
Electrical engineering,
Electronic engineering
Computer engineering
Electrical and computer engineering
Engineering disciplines