Re: Solid state gaps beginners questions? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 8 Jun 2007 12:32:19 -0700 (PDT)
From: Brett Miller <brmtesla2@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Solid state gaps beginners questions? (fwd)

Scott,

> ---------- Forwarded message ----------
> Date: Thu, 07 Jun 2007  16:30:44 -0400
> From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> To:  tesla@xxxxxxxxxx
> Subject: Solid state gaps beginners questions?
> 
> Hey  everybody,
> Since everybody is talking about this "SISG"  I have
> a few simple easy 
> to answer questions, as a "never touched solid 
> state" person.  Obviously 
> these SISGs are more efficient, lending to  much
> bigger arcs, 

Well, my understanding is that due to the fact that
the firing rate was found to be rather chaotic,
efficiency of the SISG can be difficult to quantify. 
True efficiency can only be known if an accurate duty
cycle can be derived.

> but what are 
> the streamers like?  

Well, they look and sound quite a bit like an angry
conventional disruptive coil (although mine only makes
2 inch sparks at this point), but some have reported
that the arcs are a bit thicker...maybe due to long on
times.

> Do they look like  conventional
> TC streamers, or are 
> they like the swords produced with tube  coils? 
> I've read that DRSSTC 
> streamers look exactly like  conventional streamers,
> what is the difference 
> between DRSSTC and  SISG?  

Well there are great differences in the two
topologies:

http://wiki.4hv.org/index.php/DRSSTC
http://drsstc.com/~sisg/files/SISG.pdf

...the sparks can look the same...but with the DRSSTC,
spark characteristics are determined by the IGBT gate
driver interrupter settings.  You can make them
thicker or thinner with the turn of a knob in real
time as the coil is running, and you can also vary the
break rate (BPS/PRF) in real time.  Some people (such
as Steve Ward) have run their DRSSTC's in "long pulse"
mode, which gives a gigantic spark (4+ feet in his
case)
which has the thick white plasma helix look of a tube
coil, yet is branched and long due to the low Fo of
the system.

The SISG is just a spark gap where the breakdown
voltage is set by a SIDAC string threshold rather than
the dielectric breakdown voltage of a certain air gap
distance.  It's elegant simplicity is what appeals to
me, plus the "newness" of it.  I get sick of the same
stuff.

> People have been talking
> about "triggered SISG", 
> what does  that mean?  

It is an attempt to control the break rate of the SISG
rather than relying on SIDAC breakdown alone (which
Terry found can be less than predictable).  Like the
triggered gap that Marc Metlicka made except the
energy goes through silicon dies rather than the air.

> Final question, a short while
> ago, I suggested 
> building a  rotary "full contact" spark gap, I
> haven't started it yet, but my 
> question  is this, could one simply string a whole
> bunch of transistors ?(or  
> mosfets, or whatever) in series, to obtain the
> necessary voltage rating,  and 
> than put strings in parallel for the necessary
> current rating of tank  
> discharge, (like an MMC, but with transistors) and
> then trigger the bases  of 
> all of them simultaneously with a low voltage, full
> contact "spark gap"  to 
> fire the solid gap (actually, if my knowledge serves
> me well, the  contact 
> gap would have to cease fire, or shut off power to
> the transistors  to fire 
> the main gap).  Any thoughts on this?  Do I have the
>  right idea, or do I 
> have no clue what is going on!?!  

Just make sure you read the paper below.  Terry has
figured it out for us.  It is a work of genius.

http://drsstc.com/~sisg/files/SISG.pdf

Just  curious.
> Scott Bogard.
> 
> 



       
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