If you want the thrill of doing it yourself, then you have these choices;

1    use a standard ignition coil and make and break 12 volts on it.  You may
find that the range of spark gaps is limitted.
2    Use a standard ignition coil and build a CDI type switching supply to
join to it.  You will have a broader range of spark gaps, and if you strike
with a stream of pulses, you get a dramatic display of spark.  The camera
flashes and high energy CDI ignitions are both somewhat similar in topology.
The switcher is typically a flyback switcher operating in the discontinuous
mode, and you charge a 1uF cap up to 300 to 500 VDC.  Then you stop the
switcher long enough to discharge the cap over the coil primary.  The CDI is
a bit goofy, where the cap is wired in series with the coil +, and the other
end of the cap (where the flyback dumps charge) is the point where you attach
an SCR to ground.  The coil - goes to ground as well.  There is a bit more,
such as an inductor to limit rise time, and some flyback diodes to terminate
the discharge after one pulse, so it doesn't ring for a long time.

You will have to design a flyback (usually the point were most folks veer off
of this track).

Chris Eddy

William Chops Westfield wrote:

>     I need a H.V. circuit design. The circuit must produce a spark in the
>     range of 6 to 10 K.v. to ignite propane gas. Perhaps a camera flash
>