Undoubtedly one of the few
major discoveries of humankind throughout history, electricity has changed our
lives in ways our ancestors could never imagine. Study our guide and learn
electricity basics that have changed our world.
When first starting to study
electrical theory, there are some basic questions that first come to mind: what
is electricity, how is a current produced, and what do we mean by the words
electric charge, voltage, and electric potential? The first to deal with these
matters were the famous scientists of the 19th century: Nikola Tesla, Thomas
Edison, Ernst Werner von Siemens, Alexander Graham Bell, Lord Kelvin, and many
more. These people actually set the basis for the electrical science and
engineering that ultimately changed our modern way of life.
To begin with, terms such as
electricity, electric charge and electric field require a basic knowledge of
atomic theory. Subatomic particles (electrons and protons) are considered to be
the carriers of electric charge, an inherent property of these particles that
also produces a field of forces around it known as an electric field. The
resultant field exerts attractive or repulsive forces on any other charges
placed within the field. The motion of these charges constitutes an electric
current.
The theory discussed above has
found important practical application in the design of circuits, both
electrical and electronic. An electrical circuit comprises several
interconnected electric components such as resistors, capacitors, and inductors
that form a closed circuit. When electrical current flows through this circuit,
a certain task is carried out. On the other hand, electronic circuits are far
more complex, since they comprise semiconductive elements as well.
The basic law describing the
behavior of these circuits is Ohm's law, which connects the resistance of an
element to the current that flows through it and the potential difference
across it. However, in order to study more complex electrical circuits, other
laws are also necessary to use.
The first scientist to
discover a direct relationship between electrical currents and magnetism was
Hans Christian Ørsted, back in 1821. He observed that a wire carrying an
electric current is surrounded by a magnetic field that exerts a force on a
compass needle. André-Marie Ampère also studied the phenomenon by observing
that attractive or repulsive magnetic forces are also exerted on moving charges.
In 1831, Michael Faraday
stated that the potential difference induced in a closed circuit is
proportional to the rate of change of magnetic flux through the loop. This is
known as Faraday's law of induction, and its importance lies in the fact that
electricity can be produced by using this principle. It would be needless to
stress the importance of this discovery. Visit the articles below to find out
how these principles work:
If you are interested in
building a simple electromagnet to demonstrate the theories explained in this
guide, just for fun or for educational purposes, here are a handful of articles
with all the essential information to guide you through the process:
An electric generator
transforms mechanical energy into electrical energy by using the interaction of
magnetic fields with current-carrying conductors. The phenomenon of
electromagnetic induction discovered by M. Faraday is actually the basis of
electric current generation. The following articles give an introduction on how
this principle is used and how a modern generator works.
The reverse process is used in
electric motors where electrical energy is transformed into mechanical energy.
Since both generators and motors rely on the same principle, an electrical
machine can be designed to operate as generator or motor according to our needs.
Transformers, on the other
hand, do not transform electrical energy to another form, but rather transfer
it from one circuit to another. This is possible with the use of two
inductively coupled coils belonging to each of the circuits. The mutual
induction effect, which is better described in the articles below, results in
the production of induced voltage in the secondary winding which is
proportional to its number of turns and the primary voltage.
Electricity has changed our
lives forever by allowing us to accomplish things we never imagined we could.
Although it seems that we have learned it all, electricity and electromagnetism
still hold many secrets yet to be discovered.
Have questions about the basic
concepts of electromagnetism and how electricity is used in motors,
transformers, and electrical circuits? Can you think of additional topics that
we should include here? If so, please leave a comment below.