Re: [CAD_CAM_EDM_DRO] bipolar or unipolar

At 16:21 03/04/2003 -0500, you wrote:

> > A unipolar always flows current the same direction in a coil.
>
>
>Tim: This is NOT exactly correct! The current in HALF a coil always flows
>in the same direction, but it (always!) flows the OPPOSITE direction in the
>OTHER half of that same coil! This is the POINT of the center-tapped
>"unipolar"! Gets you "bipolar results" with only one actual polarity, simply
>by "swapping ends"!

Not clear to me what "half a coil" is. Either you are talking about a coil,
or you are not talking about a coil. One half (from one end to the
centre-tap) of a centre-tapped coil is still a coil. So there was nothing
wrong with Tim's explanation.

Reminds me of an anecdote about Isaac Asimov (who as well as being a SciFi
novelist, was also a well respected scientist). On one occasion, he was
watching a colleague deliver a lecture, and was giving him some grief from
the back row. The lecturer got pissed at Asimov's interruptions, and
Asimov, to prove a point, says "OK, show me a piece of chalk". The lecturer
holds up the piece of chalk. "Now show me half a piece of chalk". The
lecturer breaks the piece of chalk in half and holds up one half. "I think
that is a piece of chalk" says Asimov triumphantly.


Regards,
Tony