Hi Doug,

> But you still need something to
> suddenly change the current path in the coil.  Doing this machanically
> may be possible, by hinging the core laminations or such, I doubt it
> would be practical.

About a million years ago I saw an ancient "magneto" which did just that....

It has a magnet buried as the center limb of a transformer, and the end pole
piece was hinged.

The magnetic field normally held the pole tightly in place, but when a lever
was moved
away (by the rotation of the cam) a spring pulled the pole piece open.

Due to the action of the spring (v/s the magnetic attraction) the pole piece
opened with an abrupt snap action,
causing a fat spark in the secondary winding.

I assumed that some manufacturer was trying to avoid a patent infringement
or some such ........

........................... Zim

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