CHECK IT OUT
63
A little history
Almost 200 years ago, the Danish physicist
Hans Christian Oersted
discovered that
electrical current and magnetism are
closely related. His experiment with a
compass and a wire with current flowing
through it opened the way to countless
important practical applications.
In action
Electromagnets are found in electric
motors, in
relays
, in electrical gener-
ators at power plants, and in power
network transformers. They are also
used in radios and televisions, record
players, microphones, telephones, and
speakers, in modern medical exam
machinery, as well as in the particle accelerators that physi-
cists are using to explore the world of subatomic building
blocks. Without risk of exaggeration, you can truly say that
our world would be a very different place without
electromagnets.
How is electricity produced
on a large scale?
If you wanted to use batteries to power subways, streetlights,
electric ovens, or the electric engines in factories, you wouldn’t
get very far. Fortunately, people discovered another way to pro-
duce electricity over 150 years ago — by using an alternating
magnetic field to generate electricity in a spool.
That is what a bicycle dynamo uses, and on a much larger scale
it is also how large electrical generators work, by rapidly rotat-
ing electromagnets past spools. The generators in power plants
are driven by turbines whose blades are in turn driven by falling
water
(in hydroelectric plants)
or by hot steam (in coal, oil, and
nuclear power plants). In wind power plants, the wind turbine
propeller drives the generator directly.
Electromagnetism
Summary of Contents for Electricity and Magnetism 620417
Page 1: ...TITELSEITE U1 EXPERIMENT MANUAL ...
Page 68: ......