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Re: Another "My First Coil" story.



Subject:     Re: Another "My First Coil" story.
      Date:  Wed, 28 May 1997 21:21:09 +1000
      From: Peter Electric <elekessy-at-macquarie.matra-dot-com.au>
        To: tesla List <tesla-at-pupman-dot-com>
References: 
           1


Tesla List wrote:
> 
> Subject:      Another "My First Coil" story.
>        Date:  Mon, 26 May 1997 22:30:54 +1000
>        From:  Phil Chalk <philoc-at-ozemail-dot-com.au>
> Organization: Secure_Logic
>          To:  tesla-at-pupman-dot-com
> 
> Greetings all,
> 
> I've finally joined the ranks of those that've actually built one,
> throwing sparks !  But........
> 
Snip> 
> With a 6" copper sphere (toilet cistern float) on top, it tunes at about
> turn 7, and throws the odd spark from the centre rib - sometimes.  If I
> put a pin on the sphere it throws sparks from there, but no longer -
> perhaps shorter - than without the sphere. A roughly hemispherical spun
> aluminium 'wok lid' about 12" diameter throws many short (<= 1") sparks
> from the rim.
> 
> 
> Phil Chalk.

I have also got a relatively "skinny" coil at 3.5" by 21" and I found
much the same thing, i.e. I got only slightly longer sparks from an 8"
sphere (glass lampshade with foil) than I got from the bare bolt. My
coil also tuned around 5 to 6 turns.

When I fitted it with a 18" by 10" inch toroid, also a Al covered
lampshade, (I'm right into lampshades) the coil tuned out at 8 turns and
really came to life - I got 30" sparks. I'm pretty new at this but IMO
you seem to get longer sparks the lower you can get the freq of the
coil. I think the guys with 6" or larger secondaries have an advantage
here.

Try the toroid and see how you go.

Peter E.