Re: Magnets

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Original poster: gary350@xxxxxxxxxxxxx

Did anyone see the TV show a few months ago about magnets.  They 
said, there was not much known about magnets 40 years ago they were 
not considered very useful.  Magnet technology has increased 30 fold 
in the past 10 years and now have 1000s of applications.  Has any 
research been done with magnets on a Tesla Coil?"

   That TV show was putting out pure uninformed nonsense.  Magnets 
(I assume you mean permanent magnets as electromagnet have no 
mysteries at all) have been thoroughly understood even at the 
theoretical level for at least 100 years and used by the billions 
over the years.  Just about every speaker in every radio built since 
1940 (and many before that) uses permanent magnet field structures 
and ALL telephone receivers ever built from the first Bell one on 
used permanent magnets in the receivers.

   What has happened in the past 40 years that a number of new 
permanent magnet materials have been developed which offer greater 
energy in a given volume and their price has become reasonable.  At 
one extreme are the ubiquitos ceramic magnets which have low energy 
but are dirt cheap and at the other would be the NdFeB magnets which 
have far more energy and are now quite affordable.

Ed