Re: Poulsen first light

["Mike Nolley" <nolleym-at-willamette.edu> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Original Poster:  Mike Nolley (nolleym-at-willamette.edu)

> Mike:
> 
> 	First time I downloaded it the whole file didn't come through.  I
> gather you are trying to use a very high >2 kV voltage source for your
> arc.  That won't do at all for such a device.  A very small arc
> oscillator I built here a number of years ago ran about 1 amp from
> rectified 120 volt line, using a 100 watt lamp as a series ballast. 
> Once the arc was struck the voltage across it drops to around 20 volts
> average.  Got the thing to put out a bit of power at 300 kHz, and it
> would oscillate (sort of) up to about 2 MHz.  Sometime I intend to
> resurrect it and do it right.....
	Riiiight...  I actually did find an arc oscillator that operated
at 5kv called the "collins" system, but I gather it didn't work all that
well, since DeForest's system seemed to be the preferred one.  It used a
low voltage ( <500v ) source.  I can see why high voltage wouldn't be
desirable after a point.  The strength of the magnetic field would control
the pitch of the negative resistance curve, and would also control how
wide the voltage swings could be.  Of course, as you increase voltage and
decrease amperage in the source, you limit the magnetic fields you can
produce, unless you use permanent magnets or electromagnets which
*aren't* powered by the source current.  I'll probably do some experiments
with higher voltages anyway, but thanks very much for the tip.  I do have
some NIB's which are incredibly strong. . . (four of these quarter sized
wonders will hold many hundreds of pounds of iron)

	--Mike 



> 
> 	Suggest you contact 
> 
> 	David Quinlan
> 	poulsen-at-mail.hicom-dot-net
> 
> A year or so ago he was building a rather good arc oscillator, and might
> be willing to share details with you.  For general information on the
> subject you might want to start at this web site:
> 
> 	http://home.luna.nl/~arjan-muil/radio/poulsen.html
> 
> 	Bottom line is that I would expect your arc to be happier running a few
> amps at 200 VDC or less, with some sort of regulator to keep the spacing
> right.  You will need a suitable ballast, of course.
> 
> Ed
> 
> 
> 
>