Re: Addendum-DC Tesla

Tesla List wrote:
> >From MALCOLM-at-directorate.wnp.ac.nzWed Jul 31 21:49:50 1996
> Date: Thu, 1 Aug 1996 11:16:09 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Addendum-DC Tesla
> I'd just like to add another thought to this.
> snip

 I wonder if we were to account for all the losses and outputs
> > from a Tesla coil in "HOT SPARK MODE" if we wouldn't find the DC output
> > would swamp the AC output in relative power?  If this were the case, the
> > DC would be the "normal mode of operation for the sparking system"!!
> At the time a discharge is initiated, the terminal has some
> arbitrary polarity. In effect you could look on it as having a large
> DC charge even though this is a momentary state of affairs.
> Make sense?
> Malcolm


You are correct, but this state changes rapidly with time.  The DC from 
the system, has to be collected on another terminal (at least as far as I 
have verified with experiment to date)  I was merely thinking out loud in 
the specific part of my post about the remote possibilty of DC charge on 
the coil's terminal!  I haven't proven this yet!


There are a nuber of ways to actually rectify AC voltage.  Many of them 
have fallen into the shadows during the lapse of years. Among the more 
efficient, real work rectifiers are the solid state diodes of which we 
are all familiar, and the thermionic emission mercury or gas vapor 
rectifiers of old.  One of the most significant of the "also rans" is 
high field emission or simply, "field emission".  If any form of 
rectification is occuring in my Tesla coil scenario, I would opt for 
this.  But the mean free path is like zip in air and this method seems 
most unlikely over the ion method of charge transferance. It might be 
significant to note that the ion blasts occur in time with the break and 
not the resoant frequency of the coil.

 This interesting method of rectification and elecron emission (field 
emission) is seeing a modern revival in HV diodes and miniature X-ray 
tubes.  All you need is a material of high work function and microscopic 
surface area to emit electrons.  High voltage isn't even needed with 
proper design!!

In the strictest sense, I am putting in AC (wall outlet) and getting DC 
and thus rectification is taking place, but not as it is currently dealt 
with at the base level of undestanding.  Nothing magic here... just an 
interesting phenomenon to investigate.

Richard Hull, TCBOR