Re: Triggered Gaps

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>


 > I think I would like to modify my SRSG coil into
 > one that uses a triggered spark gap .. thus
 > making sort of solid state.

 >>>>>>>>>>>Not really.  Not even close to solid state.

 > My understanding of the triggered spark gap is that
 > it is a single two electrode static gap with the
 > electrodes placed at such a distance that they will
 > never arc on their own at the desired arcing voltage.

 >>>>>>>>>>>Actually, triggered spark gaps will all self-fire at a specific
voltage.  They also tend to
                         self-fire during a voltage-reversal.


 > In order to facilitate an arc, a third electrode is
 > introduced. This third electrode delivers electrons
 > from a completely isolated HV circuit into the space
 > between the primary electrodes and thus triggers
 > the main spark. Kind of like an ultra high power, high
 > voltage, low resistance, fast transistor.


 > Seems easy enough to build, has anyone made one, if
 > so, how did you drive the third electrode such that
 > it promoted gap breakdown at the right times?
 > (peak and troughs of the NST AC sinewave.)

 >>>>>>>>>>>>>>Well, you're not going to build a triggered spark gap.  They
must be purchased.  However, you can build the
drive circuitry quite easily and set to trigger on a TTL or similar signal.
Basically, you need to build a high voltage pulse circuit as
triggered spark gaps can require up to 15kV or more to actually trigger the
spark.  This is usally done with a high voltage capacitor (say 400VDC)
and triggered via a cascading SCR scheme.  The 400VDC capacitor (or similar)
would then discharge through a pulse transformer to trigger
the gap.


Dan