Re: Magnifier coils

From: 	Julian Green[SMTP:julian-at-kbss.bt.co.uk]
Sent: 	Thursday, July 17, 1997 8:26 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Magnifier coils

>Hi all,
>I've heard the term magnifier coil used a number of times and I was
>wondering what exactly they are ?. How are they different from a tesla
>coil ?.

A magnifier is a three coil system.   The big voltage rise occurs in the third
coil (resonator) which is a seperate coil fed via a transmition line.

The primary and secondary coils are closely coupled so energy transfer if more
efficient.   Also being magnetically isolated from the resonator less energy
finds its way back into the primary tank circuit.

For large scale work a magnifier will work better - it seems that deminishing
returns start to set in when you scale up a tesla coil (at least they did when
I build a bigger coil).

You can build a small magnifier setup using tesla coil parts.   Use your 
secondary as the third coil and fit toroid.   Build a new primary from copper
pipe or coax do not wind a flat spiral  - wind around a piece of plastic tubing
(about 15 turns) say 7" diameter.  Wind secondary with 100 turns of wire on 5" 
plasic tube make length of this coil two times lenght of primary (chose wire
size acordingly).   Place secondary inside primary.  Connect bottom of 
secondary to RF earth.   Connect top end of secondary to bottom of resonator.
Stand resonator on plastic crate for good insulation.   Connect primary to
tesla tank circuit.   Tune by moving primary tap.

I tried this a while ago on the coffee table in the living room got good 
results, but had trouble with flash overs between top of secondary and primary
which limited spark length on the output.  Only took an evening to try.

Julian Green.