is a form of energy involving the flow of electrons. All matter is
made up of atoms, and an atom has a center, called a nucleus. The nucleus
contains positively charged particles called protons and uncharged particles
called neutrons. The nucleus of an atom is surrounded by negatively charged
particles called electrons. The negative charge of an electron is equal
to the positive charge of a proton, and the number of electrons in an atom
is usually equal to the number of protons. When the balancing force between
protons and electrons is upset by an outside force, an atom may gain or
lose an electron. When electrons are "lost" from an atom, the free movement
of these electrons constitutes an electric current.
is a basic part of nature and it is one of our most widely used forms of
energy. We get electricity, which is a secondary energy source, from the
conversion of other sources of energy, like coal, natural gas, oil, nuclear
power and other natural sources, which are called primary sources. Many
cities and towns were built alongside waterfalls (a primary source of mechanical
energy) that turned water wheels to perform work. Before electricity generation
began slightly over 100 years ago, houses were lit with kerosene lamps,
food was cooled in iceboxes, and rooms were warmed by wood-burning or coal-burning
stoves. Beginning with Benjamin Franklin's
experiment with a kite one stormy night in Philadelphia, the principles
of electricity gradually became understood. In the mid-1800s, everyone's
life changed with the invention of the electric light
bulb. Prior to 1879, electricity had been used in arc lights for
outdoor lighting. The lightbulb's invention used electricity to bring indoor
lighting to our homes.
Theory An electric generator (Long ago,
a machine that generated electricity was named "dynamo" today's preferred
term is "generator".) is a device for converting mechanical energy into
electrical energy. The process is based on the relationship between magnetism
and electricity. When a wire or any other electrically conductive
material moves across a magnetic field, an electric current occurs in the
wire. The large generators used by the electric utility industry have a
stationary conductor. A magnet attached to the end of a rotating shaft
is positioned inside a stationary conducting ring that is wrapped with
a long, continuous piece of wire. When the magnet rotates, it induces a
small electric current in each section of wire as it passes. Each section
of wire constitutes a small, separate electric conductor. All the small
currents of individual sections add up to one current of considerable size.
This current is what is used for electric power.
An electric utility power station
uses either a turbine, engine, water wheel, or other similar machine to
drive an electric generator or a device that converts mechanical or chemical
energy to electricity. Steam turbines, internal-combustion engines, gas
combustion turbines, water turbines, and wind turbines are the most common
methods to generate electricity. Continue...How
Electricity is Generated
Timeline - Electronic Inventions Timeline - important events in the
- Electric Generators Electric generators - What it is - how is a transformer
used - how it is generated - how are turbines used - how is it measured. History Long article on several inventors connected to the field and their
An electromagnet is a device in which magnetism is produced by an electric
Fields : History of Electromagnetism Until 1820, the only magnetism known was
that of iron magnets and of "lodestones", natural magnets of iron-rich
ore. It was believed that the inside of the Earth was magnetized in the same
fashion, and scientists were greatly puzzled when they found that the direction
of the compass needle at any place slowly shifted, decade by decade, suggesting
a slow variation of the Earth's magnetic field.
Electric Generator or Dynamo Michael
Faraday of England and American Joseph
Henry separately built the first laboratory models of electric generator
in 1832. Frenchmen, Hippolyte Pixii, France built
a hand-driven model of an electric generator in 1833. American, Nikola
Tesla built the first alternating-current generator in 1892.
Electronics The history of electronics began
to evolve separately from the history of electricity late in the 19th century.
The English physicist J.J. Thomson identified the electron by and the American
physicist Robert A. Millikan measured its electric charge in 1909.
Famous Inventors Involved in the
History of Electricity and Electronics
Electrostatic Devices "Static
Electricity" Page A resource page covering many unusual
electrostatic devices and generators and a lengthy list of articles and
ESD Journal An online ezine dedicated to the
history and current events of Electrostatic devices.
G. Cottrell Cottrell was the inventor of an
electrostatic precipitator called the 'Cottrell' which removed particles/pollution
smoke or gases (in smokestacks).