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Re: [TCML] triggered spark gaps


 I  AM  THE  TRIGGERED  SPARK  GAP  WHISPERER.  Well, at least I have
significant experience.  A field distortion gap is the best---easiest to
trigger and easier to build.  Visualize two brass cap (acorn) nuts, maybe
3/8, spaced just beyond breakdown.  A tungsten needle comes in from the side
with the point centered.  The trigger pulse is fed onto the needle through
an isolation cap (a little doorknob of 100 pF or so) and the needle is
biased midway between the electrodes with two big equal resistors (>10M).  A
tiny thoriated tungsten welding rod works well for this.  You can grind a
point on the end.  It would probably work well extending through the gap
with no needle point, if you see what I mean.  Keep everything symmetrical.

A trigatron gap has the needle coming just flush through a hole in one of
the electrodes, but is much more finicky.  Few if any big pulsers or Marxes
use them.

You probably know all this stuff, but here it is.  Let me know if I can
dispense any further wisdom.

--- Carl

PS--Sounds like a fun project.  Let us know how it works.

-----Original Message-----
From: Tesla <tesla-bounces@xxxxxxxxxx> On Behalf Of jimlux
Sent: Tuesday, September 18, 2018 10:46 AM
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: [TCML] triggered spark gaps

I'm getting ready to start experimenting with triggered spark gaps for a TC
- all the timing benefits of a rotary gap, but without spinning blades of

What I'd love to find, and I'm hoping the TCML hive-mind can help, is an off
the shelf "electronic ignition" module - not capacitive discharge, but
something that basically is the "points replacement" that I can drive with
an optical link (for HV isolation).

The idea is to use a 12V battery, an electronic ignition, and a conventional
ignition coil as a robust trigger pulse generator for the spark gap.

Something fancy like the MSD, which generates multiple sparks, isn't what I
want.. I want just the one pulse into the coil.

Back in the day, there were "points replacement" modules - maybe something I
can order as part of a HEI?
(after all there's the famous GMHEICSLR contest, which used the *coil* of a
HEI as the basis for a tesla coil of sorts)

Cheap is good. The ignition coils are $12 - I'm not wild about spending
$100 on what is basically a HV transistor and some biasing resistors and

(No, I don't want to build one from scratch.. been there, done that)

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