RE: A little coil

To: tesla-at-pupman-dot-com
Subject: RE: A little coil
From: "Lau, Gary" <Gary.Lau-at-compaq-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Fri, 24 Dec 1999 10:25:05 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

There are problems when the primary inductance becomes too small.  The
impedance that the cap discharges into (surge impedance) becomes very low.
This causes the current through the cap to be very high (rough on the cap)
and makes gap quenching more difficult.  Resistive losses in the tank
circuit are also higher, as these are proportional to the square of the
current(I**2 R).  But I'm afraid that I don't know what to tell you as far
as just how much constitutes "too small".

Regards, Gary Lau
Waltham, MA USA

		-----Original Message-----
		From:	Tesla List [mailto:tesla-at-pupman-dot-com]
		Sent:	Thursday, December 23, 1999 1:41 PM
		To:	tesla-at-pupman-dot-com
		Subject:	A little coil

		Original Poster: Raycroft <k.raycroft-at-worldnet.att-dot-net> 

		Here's the story:

		After building my first coil, and having much fun, I have
decided to
		build another.  But instead of going for bigger is better
(which it is),
		in the interest of $$$$ I have decided to have fun on a
different
		scale.  I recently wound a "millicoil" on a 11/16" x 4.25"
form with
		30awg wire.  With a little tiny topload it should resonate
around 3
		megahertz.  I can build a primary and cap for it.  In fact I
can even
		use a .006 mfd cap, because the primary will have small
inducance (1.5"
		dia).  Aside from having a small bandwidth to primary turns
ratio
		==>difficult to tune, I was wondering if you forsee any
problems.  I
		plan to use a spark gap, my .006 capacitor, and my first
nst: 7.5/18 (my
		current coil has graduated to 15/30).

		Thank you, and have a wonderful Christmas (I know how I'll
be spending
		my break)

		Jason Raycroft