Introduction to Electrical Engineering

Electrical engineering (sometimes referred to as electrical and
electronic 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, optoelectronics,
digital electronics, analog electronics, computer science, artificial
intelligence, control systems, electronics. The term electrical engineering may or may
not encompass electronic 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
electronic 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 conce7yrujg/jz;yeahfjrned with using electricity to
transmit information.


    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 electronic
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


Electronic 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 (of a pneumatic signal conditioner) 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 electronic engineering.

Before the invention of the integrated circuit in 1959, electronic
circuits were constructed from discrete components that could be
manipulated by humans. These discrete circuits consumed much space and
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.


      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.