Re: [Phys-l] Electron Transfer Demo

[Jeff Bigler <jcb@mit.edu>]

On 4/13/2012 2:58 AM, Bernard Cleyet wrote:
> On 2012, Apr 12, , at 20:53, Jeff Bigler wrote:
>
> > I was demonstrating an induction coil in one of my physics classes
> > today.  
>
> What type -- The reason I ask is whether its output was AC or dc  did it have an interrupter with a cap. in parallel with the points?
>
> Such are DC w a small reverse EMF.
>
> Which leads to my next question.

The output is DC.

> > At that point, because I now had a match on the end of a meter stick, I
> > thought it might be fun to see whether the current affected the flame.
> > So I lit the match and held the flame (on the end of the meter stick)
> > near the arc.  When I did this, the arc jumped into the flame.
>
> Did the arc act as a sink, i.e. from one terminal to the flame and not then to the other terminal, or did the flame divert its path but still go from one terminal tother?

As Paul Nord describes, the flame diverted the path, but the arc
continued to the other terminal.

> Is one of the secondary terminals earthed or common with one end of the primary?

The coil I used has only two DC terminals, a potentiometer for adjusting
the voltage, and a "positive/negative" switch for reversing the polarity.

-- 
Jeff Bigler
"Magic" is what we call Science before we understand it.
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