Re: Decrement (?) (Re: (Fwd) RE: Longitudinal Waves)

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Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Cory,

On 18 Feb 2002, at 1:40, Tesla list wrote:

> Original poster: "Cory Roussel by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <imcuddlycory-at-yahoo-dot-com>
> 
> Hello Coilers,
> 
> Here is a VERY basic question that has BOTHERED ME for
> a long time but i never really got to thinking about
> it too much... In a transformer, why is it that the
> poles are reversed on every cycle (IE AC)!?  Why is it
> necisary that the voltage be changed, and not
> constant...  I dunno these are very simple and i just
> cant figure out even though they are SO simple...

Your question is not really specific enough. Are you asking why the 
voltage across an inductor with energy stored in its magnetic field 
changes polarity when the current is interrupted? Or are you asking 
why a transformer *has* to run with an AC (or interrupted DC) 
waveform applied?
 
      The answer to the first is that the collapsing magnetic field 
tries to keep current flowing in the same direction as the inductor 
becomes an energy source.
      The answer to the second is that it requires a changing 
magnetic field to induce a voltage in the windings.

Regards,
Malcolm
<snip>