Electronics engineering, also referred to as
electronic engineering is an
engineering discipline which uses the scientific
knowledge of the behavior and effects of
electrons to develop components, devices, systems,
or equipment (as in
electron tubes,
transistors,
integrated circuits, and
printed circuit boards) that uses
electricity as part of its driving force. Both terms denote a broad
engineering field that encompasses many subfields including those
that deal with
power,
instrumentation engineering,
telecommunications,
semiconductor circuit design, and many others.
The term also covers a large part of
electrical engineering degree courses
as studied at most European universities. In the U.S., however,
electrical engineering encompasses all electrical disciplines
including electronics. The
Institute of
Electrical and Electronics Engineers is one of the most
important and influential organizations for electronic engineers.
Indian
universities
have separate departments for Electronics Engineering.
Terminology
The name
electrical
engineering is still used to cover electronic engineering
amongst some of the older (notably American and Australian)
universities and graduates there are called
electrical engineers. Some people
believe the term 'electrical engineer' should be reserved for those
having specialized in power and heavy current or high voltage
engineering, while others believe that power is just one subset of
electrical engineering (and indeed the term 'power engineering' is
used in that industry) as well as 'electrical distribution
engineering'. Again, in recent years there has been a growth of new
separate-entry degree courses such as '
information engineering' and
'
communication systems
engineering', often followed by academic departments of similar
name.
Most European universities now refer to
electrical engineering as power
engineers and make a distinction between Electrical and Electronics
Engineering. Beginning in the 1980s, the term
computer engineer was often used to refer
to electronic or information engineers. However, Computer
Engineering is now considered a subset of Electronics Engineering
and the term is now becoming archaic.
History of electronic engineering
Electronic engineering as a profession sprang from technological
improvements in the
telegraph industry in
the late 1800s and the
radio and the
telephone industries in the early 1900s. People
were attracted to radio by the technical fascination it inspired,
first in receiving and then in transmitting. Many who went into
broadcasting in the 1920s were only 'amateurs' in the period before
World War I.
The modern discipline of electronic engineering was to a large
extent born out of telephone, radio, and
television equipment development and the large
amount of electronic systems development during
World War II of
radar,
sonar, communication systems, and advanced
munitions and weapon systems. In the interwar years, the subject
was known as
radio engineering and
it was only in the late 1950s that the term
electronic
engineering started to emerge.
The
electronic laboratories (Bell Labs
in the United States for instance) created and
subsidized by large corporations in the industries of radio,
television, and telephone equipment began churning out a series of
electronic advances. In 1948, came the transistor and in
1960, the IC to revolutionize the electronic industry. In the UK,
the subject of electronic engineering became distinct from
electrical engineering as a
university degree subject around 1960. Before
this time, students of electronics and related subjects like radio
and telecommunications had to enroll in the
electrical engineering department of
the university as no university had departments of electronics.
Electrical engineering was the nearest subject with which
electronic engineering could be aligned, although the similarities
in subjects covered (except mathematics and electromagnetism)
lasted only for the first year of the three-year course.
Early electronics
1896 Marconi patent
In 1893,
Nikola Tesla made the first
public demonstration of radio communication. Addressing the
Franklin Institute in Philadelphia and the National Electric Light
Association, he described and demonstrated in detail the principles
of radio communication. In 1896,
Guglielmo Marconi went on to develop a
practical and widely used radio system. In 1904,
John Ambrose Fleming, the first
professor of electrical Engineering at University College London,
invented the first
radio tube, the
diode. One year later, in 1906,
Robert von Lieben and
Lee De Forest independently developed the
amplifier tube, called the
triode.
Electronics is often considered to have
begun when
Lee De Forest invented the
vacuum tube in 1907. Within 10 years,
his device was used in radio
transmitters and
receivers as well as systems for long
distance
telephone calls. In 1912,
Edwin H. Armstrong invented the
regenerative feedback amplifier and
oscillator; he also invented
the
superheterodyne radio
receiver and could be considered the father of modern radio.
Vacuum
tubes remained the preferred amplifying device for 40 years, until
researchers working for William
Shockley at Bell
Labs invented the transistor
in 1947. In the following years, transistors made small
portable
radios, or
transistor radios, possible as well as
allowing more powerful
mainframe
computers to be built. Transistors were smaller and required
lower
voltages than vacuum
tubes to work. In the interwar years the subject of electronics was
dominated by the worldwide interest in
radio and to some
extent telephone and telegraph communications. The terms 'wireless'
and 'radio' were then used to refer to anything electronic. There
were indeed few non-military applications of electronics beyond
radio at that time until the advent of television. The subject was
not even offered as a separate university degree subject until
about 1960.
Prior to
World War II, the subject was
commonly known as 'radio engineering' and basically was restricted
to aspects of communications and
RADAR,
commercial radio and early television. At this time, study of radio
engineering at universities could only be undertaken as part of a
physics degree.Later, in post war years, as
consumer devices began to be developed, the field broadened to
include modern TV,
audio systems,
Hi-Fi and latterly computers and
microprocessors. In the mid to late 1950s,
the term radio engineering gradually gave way to the name
electronic engineering, which then became a stand alone university
degree subject, usually taught alongside electrical engineering
with which it had become associated due to some similarities.
Before the invention of the
integrated circuit in 1959, electronic
circuits were constructed from discrete components that could be
manipulated by hand. These non-integrated circuits consumed much
space and
power, were prone to
failure and were limited in speed although they are still common in
simple 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.
Tubes or valves
The vacuum tube detector
The invention of the triode amplifier, generator, and detector made
audio communication by radio practical. (
Reginald Fessenden's 1906 transmissions
used an electro-mechanical
alternator.)
The first known radio news program was broadcast 31 August 1920 by
station 8MK, the unlicensed predecessor of WWJ (AM) in Detroit,
Michigan. Regular wireless broadcasts for entertainment commenced
in 1922 from the
Marconi
Research Centre at Writtle near Chelmsford, England.
While some early radios used some type of amplification through
electric current or battery, through the mid 1920s the most common
type of receiver was the crystal set. In the 1920s, amplifying
vacuum tubes revolutionized both radio receivers and
transmitters.
Television
In 1928
Philo Farnsworth made the
first public demonstration of a purely
electronic
television. During the 1930s several countries began
broadcasting, and after World War II it spread to millions of
receivers, eventually worldwide. Ever since then, electronics have
been fully present in television devices.
Modern televisions and video displays have evolved from bulky
electron tube technology to use more compact devices, such as
plasma and
LCD displays. The trend is for even lower power
devices such as the
organic
light-emitting diode displays, and it is most likely to replace
the LCD and plasma technologies.
Radar and radio location
During
World War II many efforts were
expended in the electronic location of enemy targets and aircraft.
These included radio beam guidance of bombers, electronic counter
measures, early radar systems etc. During this time very little if
any effort was expended on consumer electronics developments.
Computers
In 1941,
Konrad Zuse presented the
Z3, the world's first functional
computer.
After the Colossus computer in 1943, the ENIAC
(Electronic
Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed in 1946, beginning the
computing era. The arithmetic performance of these machines
allowed engineers to develop completely new technologies and
achieve new objectives.
Early examples include the Apollo missions and the NASA
moon
landing.
Transistors
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 1959 by
Jack
Kilby.
Microprocessors
In 1969,
Ted Hoff conceived the commercial
microprocessor at Intel
and thus
ignited the development of the personal computer. Hoff's
invention was part of an order by a Japanese company for a desktop
programmable electronic calculator, which Hoff wanted to build as
cheaply as possible. The first realization of the microprocessor
was the
Intel 4004, a 4-bit processor, in
1969, but only in 1973 did the
Intel
8080, an 8-bit processor, make the building of the first
personal computer, the
MITS Altair 8800, possible. The first PC was
announced to the general public on the cover of the January 1975
issue of
Popular
Electronics.
Mechatronics would have
a good fortune in the near future.
Many electronics engineers today specialize in the development of
programs for microprocessor based electronic systems, known as
embedded systems. Due to the
detailed knowledge of the hardware that is required for doing this,
it is normally done by electronics engineers and not
software engineers. Software engineers
typically know and use microprocessors only at a conceptual level.
Electronics engineers who exclusively carry out the role of
programming embedded systems or microprocessors are referred to as
"
embedded systems engineers", or
"
firmware engineers".
Electronics
In the field of electronic engineering, engineers design and test
circuits that use the
electromagnetic properties of
electrical components such as
resistors,
capacitors,
inductors,
diodes and
transistors to achieve a particular
functionality. The
tuner
circuit, which allows the user of a
radio
to
filter out all but a single
station, is just one example of such a circuit.
In designing an integrated circuit, electronics engineers first
construct circuit
schematics that specify
the electrical components and describe the interconnections between
them. When completed,
VLSI engineers convert the
schematics into actual layouts, which map the layers of various
conductor and
semiconductor materials needed to construct
the circuit. The conversion from schematics to layouts can be done
by
software (see
electronic design automation)
but very often requires human fine-tuning to decrease space and
power consumption. Once the layout is complete, it can be sent to a
fabrication plant for
manufacturing.
Integrated circuits and other
electrical components can then be assembled on
printed circuit boards to form more
complicated circuits. Today, printed circuit boards are found in
most electronic devices including
televisions,
computers
and
audio player.
Typical electronic engineering undergraduate syllabus
Apart from electromagnetics and network theory, other items in the
syllabus are particular to
electronics engineering course.
Electrical engineering courses have other specialisms such
as
machines,
power generation and
distribution. Note that the
following list does not include the extensive engineering
mathematics curriculum that is a prerequisite to a degree.
Electromagnetics
Elements of
vector calculus:
divergence and
curl;
Gauss'
and
Stokes' theorems,
Maxwell's equations: differential and
integral forms.
Wave equation,
Poynting vector.
Plane waves: propagation through various media;
reflection and
refraction;
phase
and
group velocity;
skin depth.
Transmission lines:
characteristic impedance; impedance
transformation;
Smith chart;
impedance matching; pulse excitation.
Waveguides: modes in rectangular
waveguides;
boundary conditions;
cut-off frequencies;
dispersion relations. Antennas:
Dipole antennas;
antenna arrays; radiation pattern; reciprocity
theorem,
antenna gain.
Network analysis
Network graphs: matrices associated with graphs; incidence,
fundamental cut set and fundamental circuit matrices. Solution
methods: nodal and mesh analysis. Network theorems: superposition,
Thevenin and Norton's maximum power transfer, Wye-Delta
transformation. Steady state sinusoidal analysis using phasors.
Linear constant coefficient differential equations; time domain
analysis of simple RLC circuits, Solution of network equations
using
Laplace transform: frequency
domain analysis of RLC circuits. 2-port network parameters: driving
point and transfer functions. State equations for networks.
Electronic devices and circuits
Electronic devices: Energy bands in silicon,
intrinsic and extrinsic silicon. Carrier transport in silicon:
diffusion current, drift current, mobility, resistivity. Generation
and recombination of carriers.
p-n
junction diode,
Zener diode,
tunnel diode,
BJT,
JFET,
MOS
capacitor,
MOSFET,
LED,
p-i-n and
avalanche photo diode, LASERs. Device
technology:
integrated
circuit fabrication process, oxidation, diffusion,
ion implantation, photolithography, n-tub,
p-tub and twin-tub CMOS process.
Analog circuits: Equivalent circuits (large and
small-signal) of diodes, BJTs, JFETs, and MOSFETs. Simple diode
circuits, clipping, clamping, rectifier. Biasing and bias stability
of transistor and FET amplifiers. Amplifiers: single-and
multi-stage, differential, operational, feedback and power.
Analysis of amplifiers; frequency response of amplifiers. Simple
op-amp circuits. Filters. Sinusoidal
oscillators; criterion for oscillation; single-transistor and
op-amp configurations. Function generators and wave-shaping
circuits, Power supplies.
Digital circuits: of
Boolean functions; logic gates digital IC
families (
DTL,
TTL,
ECL,
MOS,
CMOS).
Combinational circuits: arithmetic circuits, code converters,
multiplexers and
decoders.
Sequential
circuits: latches and flip-flops, counters and shift-registers.
Sample and hold circuits,
ADC,
DAC.
Semiconductor memories.
Microprocessor 8086: architecture,
programming, memory and I/O interfacing.
Signals and systems
Definitions and properties of
Laplace
transform, continuous-time and discrete-time
Fourier series, continuous-time and
discrete-time
Fourier Transform,
z-transform.
Sampling theorems.
Linear Time-Invariant Systems:
definitions and properties; causality, stability, impulse response,
convolution, poles and zeros frequency response, group delay, phase
delay. Signal transmission through LTI systems. Random signals and
noise:
probability,
random variables,
probability density function,
autocorrelation,
power spectral
density, function analogy between vectors &
functions.
Control systems
Basic control system components; block diagrammatic description,
reduction of block diagrams — Mason's rule. Open loop and closed
loop (negative unity feedback) systems and stability analysis of
these systems. Signal flow graphs and their use in determining
transfer functions of systems; transient and steady state analysis
of LTI control systems and frequency response. Analysis of
steady-state disturbance rejection and noise sensitivity.
Tools and techniques for LTI control system analysis and design:
root loci,
Routh-Hurwitz stability
criterion, Bode and
Nyquist plots.
Control system compensators: elements of lead and lag compensation,
elements of
Proportional-Integral-Derivative
controller (PID). Discretization of continuous time systems
using
Zero-order hold (
ZOH) and ADCs for digital controller implementation.
Limitations of digital controllers: aliasing. State variable
representation and solution of state equation of LTI control
systems. Linearization of Nonlinear dynamical systems with
state-space realizations in both frequency and time domains.
Fundamental concepts of controllability and observability for
MIMO LTI systems. State space realizations:
observable and controllable canonical form.
Ackerman's function for state-feedback
pole placement. Design of full order and reduced order
estimators.
Communications
Analog communication systems: amplitude and
angle modulation and demodulation systems,
spectral analysis of these
operations,
superheterodyne noise
conditions.
Digital communication systems: pulse code modulation ,
Differential Pulse
Code Modulation ([[DPCM),
Delta
modulation (
DM), digital modulation
schemes-amplitude, phase and frequency shift keying schemes
(
ASK,
PSK,
FSK), matched filter receivers,
bandwidth consideration and probability of error calculations for
these schemes,
GSM,
TDMA.
Education and training
Electronics engineers typically possess an
academic degree with a major in electronic
engineering. The length of study for such a degree is usually three
or four years and the completed degree may be designated as a
Bachelor of Engineering, Bachelor of Science, Bachelor of Applied
Science, or Bachelor of Technology depending upon the university.
Many UK universities also offer Master of Engineering (
MEng) degrees at undergraduate level.
The degree generally includes units covering
physics,
chemistry,
mathematics,
project management and specific topics in
electrical engineering.
Initially such topics cover most, if not all, of the subfields of
electronic engineering. Students then choose to specialize in one
or more subfields towards the end of the degree.
Some electronics engineers also choose to pursue a
postgraduate degree such as a Master of Science
(
MSc), Doctor of Philosophy in Engineering
(
PhD), or an Engineering Doctorate (
EngD). The Master degree is being introduced in some
European and American Universities as a first degree and the
differentiation of an engineer with graduate and postgraduate
studies is often difficult. In these cases, experience is taken
into account. The Master'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 most countries, a Bachelor's degree in engineering represents
the first step towards 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
(including work experience requirements) before being certified.
Once certified the engineer is designated the title of Professional
Engineer (in the United States, Canada and South Africa), Chartered
Engineer or Incorporated Engineer (in the United Kingdom, Ireland,
India and Zimbabwe), Chartered Professional Engineer (in Australia)
or European Engineer (in much of the European Union).
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
electronic systems.Although most electronic 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.
Professional bodies
Professional bodies of note for electrical engineers include the
Institute of
Electrical and Electronics Engineers (IEEE) and the
Institution of Electrical
Engineers , now the Institution of Engineering and
Technology(IET). The
IEEE claims to produce 30
percent of the world's literature in electrical/electronic
engineering, has over 370,000 members, and holds more than 450 IEEE
sponsored or cosponsored conferences worldwide each year.
Modern electronic engineering
Electronic engineering in Europe is a very broad field that
encompasses many subfields including those that deal with,
electronic devices and
circuit
design,
control systems,
electronics and
telecommunications,
computer systems, embedded
software etc. Many European universities now have
departments of electronics that are completely separate from their
respective departments of electrical engineering.
Subfields
Electronic engineering has many subfields. This section describes
some of the most popular subfields in electronic engineering;
although there are engineers who focus exclusively on one subfield,
there are also many who focus on a combination of subfields.
Overview of electronic engineering
Electronic engineering involves the design and
testing of
electronic circuits
that use the
electronic properties of
components such as
resistors,
capacitors,
inductors,
diodes and
transistors to achieve a particular
functionality.
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 checking and
error detection of digital signals.
Telecommunications engineering deals with the
transmission of
information across a
channel such as a
co-axial cable,
optical
fiber 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.
Control engineering has a wide range of
applications from the flight and propulsion systems of
commercial airplanes to the
cruise control present in many modern
cars. It also plays an important role in
industrial automation.
Control engineers often utilize
feedback
when designing
control systems. For
example, in a
car with
cruise control the vehicle's
speed is continuously monitored and fed back to the
system which adjusts the
engine's power output
accordingly. Where there is regular feedback,
control theory can be used to determine how
the system responds to such feedback.
Instrumentation engineering deals with the design
of devices to measure physical quantities such as
pressure,
flow and
temperature. These devices are known as
instrumentation.
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.
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.
Project engineering
For most engineers not involved at the cutting edge of system
design and development, 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 electronics engineers are just as varied as the
types of work they do. Electronics engineers may be found in the
pristine laboratory environment of a fabrication plant, the offices
of a consulting firm or in a research laboratory. During their
working life, electronics engineers may find themselves supervising
a wide range of individuals including scientists, electricians,
computer programmers and other engineers.
Obsolescence of technical skills is a serious concern for
electronics 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. And these are mostly used in the field of consumer
electronics products.
See also
References
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