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[[File:Permanent Magnets_1.jpg|thumb|200px|right|Permanent Magnets]] | |||
[[File:Permanent Magnets_2.jpg|thumb|200px|right|Permanent Magnets in Motors]] | |||
'''Permanent Magnets''' are magnets which retain magnetism even after the magnetizing field strength is removed. Permanent magnets are used in equipments such as speakers, data storage devices, generators, etc, etc. | |||
While Permanent magnets too get magnetized the same way as electromagnets, they are made of special material which have very high retentivity which enable them to retain magnetism long after the magnetizing field is removed. The first permanent magnets were made from magnetite, an ore of iron which gets naturally magnetized by the earth's magnetic field. | |||
Later, better materials such as Alnico (an alloy of Aluminium, Nickel and Cobalt) were used. | |||
The 1970s saw the development of ceramic materials such as barium ferrite and strontium ferrite . These materials have the advantage of high formability, i.e. they can be made into any shape and size without the need for expensive machining. These magnets can also be made flexible adding the ceramic powder in a binding material such as PVC or rubber. | |||
==Applications== | |||
Permanent magnets are important for their industrial uses especially when it comes to power generation and electric motors. The induction process for turbines and generators needs permanent magnets to turn mechanical motion into energy. They are also important for electric motors in many electronics using the reverse of the induction of electric current to make mechanical energy. As you can see without the permanent magnet we would not be able to take full advantage of the capabilities of electricity in modern devices. | |||
==Video== | |||
<youtube>Kx187qlNkkw</youtube> | |||