Re: new secondary
Tesla List wrote:
> Original Poster: "Joe Macmurchie" <jrmac-at-home-dot-com>
> I introduced myself a while back and now it's time to fess up. I've been
> playing but not reporting on progress. I have got some pictures to put on my
> website "real soon now". I'm nearly ready to jag in my 10Kv 28ma OBIT and
> try my 12Kv 60ma neon. I've gotten solid discharge sparks up to about 8.5
> inches and spay type sparks up to about a foot or so. I don't know if that's
> good for an OBIT or not, I'm using salt water caps so far.
> I made my first secondary on a 4 inch piece of clear Plexiglas tube and
> coated it with spay acrylic varnish. It seems to work OK but I wonder if the
> clear acrylic spay was as good as any to use? It looks fine.
> My main reason for a message right now is this:
> I had some 22 gauge magnet wire left on the spool and decided to wind
> another secondary on a piece of 6.25 inch OD PVC drain pipe. I was shooting
> for the magic 24 inches but ran out of wire at 22 and one half inches of
> coil. Is a 24 incher really preferred or would a 22.5 work just as well. I
> want to decide now before I go any further with it. I've got a lathe setup
> now so winding takes no time at all.
> Any and all suggestions appreciated.
OF COURSE 22-1/2" will work, or 12", or 36". Requirement is that the
primary circuit be reasonant at the same frequency as the secondary. In
you case I calculate that the self-resonant frequency without any added
secondary capacitance should be of the order of 324 kHz; the inductance
of the secondary is about 24 mH. Any notion that any specific winding
length or ratio of resonant wavelength to total length of wire on the
secondary is critical is nonsense. Main requirement is resonance.