Encyclopedia
- This article treats electronic engineering as a subfield of electrical engineering, though this is not typical use in some areas. See electrical engineering for details.
Electrical engineering is a professional engineering discipline that deals with the study and application of
electricity,
electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century with the commercialization of the electric
telegraph and electrical power supply. The field now covers a range of sub-disciplines including those that deal with
power,
software engineering, optoelectronics,
digital electronics, analogue electronics,
artificial intelligence, control systems,
electronics, signal processing and
telecommunications.
The term
electrical engineering may or may not encompass
electronics engineering. Where a distinction is made, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as
power transmission and
motor control, whereas electronics engineering deals with the study of small-scale electronic systems including
computers and
integrated circuits. Another way of looking at the distinction is that electrical engineers are usually concerned with using electricity to transmit energy, while electronics engineers are concerned with using electricity to transmit information.
With the continuing proliferation of electronic systems in everyday life and humanity's increasing dependency on electricity as an energy source, electrical engineering has evolved into one of the most important and lucrative areas of development. Furthermore it is considered to be one of the most difficult and challenging academic fields to enter at University level, especially due to the extremely rigorous formal training in
mathematics,
physics, computer science and industrial and laboratory training required to become a chartered electrical engineer. It should be noted that unlike many pure science and mathematical disciplines, electrical and electronic engineering necessitates the practising student to not only build a solid theoretical foundation but also be proficient in design and implementation of technical ideas. With the growth of environmentalism, electrical engineers not only have to consider technical proficiency in their design and implementation but also the environmental implications of their design considerations, this has made the designing process even more complex for an engineer.
History
Early developments
Electricity has been a subject of scientific interest since at least the 17th century, but it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of
Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor,
Michael Faraday, the discoverer of electromagnetic induction in 1831, and
James Clerk Maxwell, who in 1873 published a unified theory of electricity and
magnetism in his treatise on
Electricity and Magnetism.
During these years, the study of electricity was largely considered to be a subfield of
physics. It was not until the late 19th century that
universities started to offer degrees in electrical engineering. The
Darmstadt University of Technology founded the first chair and the first faculty of electrical engineering worldwide in 1882. In 1883
Darmstadt University of Technology and
Cornell University introduced the world's first courses of study in electrical engineering and in 1885 the
University College London founded the first chair of electrical engineering in the
United Kingdom. The
University of Missouri subsequently established the first department of electrical engineering in the United States in 1886.
During this period, the work concerning electrical engineering increased dramatically. In 1882,
Edison switched on the world's first large-scale electrical supply network that provided 110 volts
direct current to fifty-nine customers in lower Manhattan. In 1887,
Nikola Tesla filed a number of patents related to a competing form of power distribution known as
alternating current. In the following years a bitter rivalry between Tesla and Edison, known as the "
War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.
The efforts of the two did much to further electrical engineering—Tesla's work on
induction motors and
polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the
stock ticker proved lucrative for his company, which ultimately became
General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge.
Modern developments
Emergence of radio and electronics
During the
development of radio, many scientists and inventors contributed to
radio technology and electronics. In his classic UHF experiments of 1888,
Heinrich Hertz transmitted and detected
radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point . In 1897,
Karl Ferdinand Braun introduced the
cathode ray tube as part of an
oscilliscope, a crucial enabling technology for
electronic television. John Fleming invented the first radio tube, the
diode, in 1904. Two years later,
Robert von Lieben and
Lee De Forest independently developed the amplifier tube, called the
triode. In 1920 Albert Hull developed the
magnetron which would eventually lead to the development of the
microwave oven in 1946 by Percy Spencer. In 1934 the British military began to make strides towards
radar , under the direction of Dr Wimperis culminating in the operation of the first radar station at Bawdsey in August 1936.
In 1941
Konrad Zuse presented the Z3, the world's first fully functional and programmable computer. In 1946 the
ENIAC of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the
Apollo missions and the
NASA moon landing.
The invention of the transistor in 1947 by
William B. Shockley,
John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the
integrated circuit in 1958 by
Jack Kilby and independently in 1959 by
Robert Noyce. In 1968 Marcian Hoff invented the first
microprocessor at
Intel and thus ignited the development of the
personal computer. The first realization of the microprocessor was the
Intel 4004, a 4-bit processor developed in 1971, but only in 1973 did the
Intel 8080, an 8-bit processor, make the building of the first personal computer, the
Altair 8800, possible.
Education
Electrical engineers typically possess an academic degree with a major in electrical engineering. 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 Engineering, Bachelor of Science, Bachelor of Technology or Bachelor of Applied Science depending upon the university. The degree generally includes units covering
physics,
mathematics, project management and specific topics in electrical engineering. Initially such topics cover most, if not all, of the sub-disciplines of electrical engineering. Students then choose to specialize in one or more sub-disciplines towards the end of the degree.
Some electrical engineers also choose to pursue a postgraduate degree such as a Master of Engineering/Master of Science, a Master of Engineering Management, a Doctor of Philosophy in Engineering or an Engineer's degree. The Master and Engineer's degree may consist of either research, coursework or a mixture of the two. The Doctor of Philosophy consists of a significant research component and is often viewed as the entry point to
academia. In the United Kingdom and various other European countries, the Master of Engineering is often considered an undergraduate degree of slightly longer duration than the Bachelor of Engineering.
Practicing engineers
In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body. After completing a certified degree program the engineer must satisfy a range of requirements before being certified. Once certified the engineer is designated the title of Professional Engineer , Chartered Engineer , Chartered Professional Engineer or European Engineer .
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients". This requirement is enforced by state and provincial legislation such as
Quebec's Engineers Act. In other countries, such as Australia, 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. In cases where an engineer's work fails he or she may be subject to the
tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the
Institute of Electrical and Electronics Engineers and the
Institution of Electrical Engineers . The IEEE claims to produce 30 percent of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 300 conferences annually. The IEE publishes 14 journals, has a worldwide membership of 120,000, 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.
In countries such as
Australia,
Canada and the
United States electrical engineers make up around 0.25% of the labour force . Outside of these countries, it is difficult to gauge the demographics of the profession due to less meticulous reporting on labour statistics. However, in terms of electrical engineering graduates per-capita, electrical engineering graduates would probably be most numerous in countries such as
Taiwan,
Japan and
South Korea.
Tools and work
From the
Global Positioning System to electric power generation, electrical engineers are responsible for a wide range of technologies. They design, develop, test and supervise the deployment of electrical systems and electronic devices. For example, they may work on the design of
telecommunication systems, the operation of
electric power stations, the
lighting and
wiring of buildings, the design of household appliances or the electrical
control of industrial machinery.
Fundamental to the discipline are the sciences of
physics and
mathematics as these help to obtain both a qualitative and
quantitative description of how such systems will work. Today most engineering work involves the use of
computers and it is commonplace to use
computer-aided design programs when designing electrical systems. Nevertheless, the ability to sketch ideas is still invaluable for quickly communicating with others.
Although most electrical engineers will understand basic circuit theory , the theories employed by engineers generally depend upon the work they do. For example,
quantum mechanics and solid state physics might be relevant to an engineer working on VLSI , but are largely irrelevant to engineers working with macroscopic electrical systems. Even circuit theory may not be relevant to a person designing telecommunication systems that use off-the-shelf components. Perhaps the most important technical skills for electrical engineers are reflected in university programs, which emphasize strong numerical skills,
computer literacy and the ability to understand the technical language and concepts that relate to electrical engineering.
For most engineers technical work accounts for only a fraction of the work they do. A lot of time is also spent on tasks such as discussing proposals with clients, preparing budgets and determining project schedules. Many senior engineers manage a team of technicians or other engineers and for this reason project management skills are important. Most engineering projects involve some form of documentation and strong written communication skills are therefore very important.
The workplaces of electrical 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, 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.
Sub-disciplines
Electrical engineering has many sub-disciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these sub-disciplines, many deal with a combination of them. Sometimes certain fields, such as electronics engineering and computer engineering, are considered separate disciplines in their own right.
Power
Power engineering deals with the generation,
transmission and
distribution of
electricity as well as the design of a range of related devices. These include
transformers,
electric generators,
electric motors and power electronics. In many regions of the world, governments maintain an electrical network called a
power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it. Such systems are called
on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called
off-grid power systems, which in some cases are preferable to on-grid systems.
Control
Control engineering focuses on the modelling of a diverse range of
dynamic systems and the design of controllers that will cause these systems to behave in the desired manner. To implement such controllers electrical engineers may use electrical circuits, digital signal processors and
microcontrollers.
Control engineering has a wide range of applications from the flight and propulsion systems of
commercial airliners to the
cruise control present in many modern
automobiles. It also plays an important role in
industrial automation.
Control engineers often utilize feedback when designing control systems. For example, in an
automobile with
cruise control the vehicle's speed is continuously monitored and fed back to the system which adjusts the
motor's speed accordingly. Where there is regular feedback,
control theory can be used to determine how the system responds to such feedback.
Electronics
Electronics engineering involves the design and testing of electronic circuits that use the properties of components such as
resistors,
capacitors,
inductors,
diodes and
transistors to achieve a particular functionality. The
tuned circuit, which allows the user of a
radio to
filter out all but a single station, is just one example of such a circuit. Another example is shown in the adjacent photograph.
Prior to the second world war, the subject was commonly known as
radio engineering and basically was restricted to aspects of communications and
radar,
commercial radio and
early television. Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems,
computers and
microprocessors. In the mid to late 1950s, the term
radio engineering gradually gave way to the name
electronics engineering.
Before the invention of the
integrated circuit in 1959, electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and
power and were limited in speed, although they are still common in some applications. By contrast,
integrated circuits packed a large number—often millions—of tiny electrical components, mainly
transistors, into a small chip around the size of a
coin. This allowed for the powerful
computers and other electronic devices we see today.
Microelectronics
Microelectronics engineering deals with the design of very small electronic components for use in an
integrated circuit or sometimes for use on their own as a general electronic component. The most common microelectronic components are
semiconductor transistors, although all main electronic components can be created at a microscopic level.
Most components are designed by determining processes to mix silicon with other
chemical elements to create a desired electromagnetic effect. For this reason microelectronics involves a significant amount of
quantum mechanics and
chemistry.
Signal processing
Signal processing deals with the analysis and manipulation of signals. Signals can be either analog, in which case the signal varies continuously according to the information, or
digital, in which case the signal varies according to a series of discrete values representing the information. For analog signals, signal processing may involve the amplification and
filtering of audio signals for audio equipment or the modulation and demodulation of signals for
telecommunications. For digital signals, signal processing may involve the compression,
error detection and
error correction of digitally sampled signals.
Telecommunications
Telecommunications engineering focuses on the transmission of information across a channel such as a
coax cable,
optical fibre or free space. Transmissions across free space require information to be encoded in a carrier wave in order to shift the information to a carrier frequency suitable for transmission, this is known as modulation. Popular analog modulation techniques include
amplitude modulation and
frequency modulation. The choice of modulation affects the cost and performance of a system and these two factors must be balanced carefully by the engineer.
Once the transmission characteristics of a system are determined, telecommunication engineers design the
transmitters and receivers needed for such systems. These two are sometimes combined to form a two-way communication device known as a transceiver. A key consideration in the design of transmitters is their power consumption as this is closely related to their signal strength. If the signal strength of a transmitter is insufficient the signal's information will be corrupted by noise.
Instrumentation engineering
Instrumentation engineering deals with the design of devices to measure physical quantities such as
pressure, flow and temperature. The design of such instrumentation requires a good understanding of
physics that often extends beyond electromagnetic theory. For example,
radar guns use the
Doppler effect to measure the speed of oncoming vehicles. Similarly,
thermocouples use the
Peltier-Seebeck effect to measure the temperature difference between two points.
Often instrumentation is not used by itself, but instead as the sensors of larger electrical systems. For example, a thermocouple might be used to help ensure a furnace's temperature remains constant. For this reason, instrumentation engineering is often viewed as the counterpart of control engineering.
Computers
Computer engineering deals with the design of
computers and computer systems. This may involve the design of new hardware, the design of
PDAs or the use of computers to control an industrial plant. Computer engineers may also work on a system's
software. However, the design of complex software systems is often the domain of
software engineering, which is usually considered a separate discipline.
Desktop computers represent a tiny fraction of the devices a computer engineer might work on, as computer-like architectures are now found in a range of devices including
video game consoles and
DVD players.
Related disciplines
Mechatronics is an engineering discipline which deals with the convergence of electrical and
mechanical systems. Such combined systems are known as electromechanical systems and have widespread adoption. Examples include
automated manufacturing systems,
heating, ventilation and air-conditioning systems and various subsystems of
aircraft and
automobiles.
The term
mechatronics is typically used to refer to macroscopic systems but futurists have predicted the emergence of very small electromechanical devices. Already such small devices, known as
micro electromechanical systems , are used in automobiles to tell
airbags when to deploy, in
digital projectors to create sharper images and in
inkjet printers to create nozzles for high-definition printing. In the future it is hoped the devices will help build tiny implantable medical devices and improve optical communication.
Biomedical engineering is another related discipline, concerned with the design of medical equipment. This includes fixed equipment such as
ventilators,
MRI scanners and
electrocardiograph monitors as well as mobile equipment such as
cochlear implants,
artificial pacemakers and
artificial hearts.
See also
