Capacitance of a 16oz SW bottle cap

To: tesla-at-pupman-dot-com
Subject: Capacitance of a 16oz SW bottle cap
From: Gary Lau 24-Feb-1999 1210 <lau-at-hdecad.ENET.dec-dot-com> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Wed, 24 Feb 1999 16:05:05 -0700
Approved: twf-at-verinet-dot-com

As a point of reference, I built a quick salt water cap out of a 16 oz
Nestea glass bottle.  The bottle measured 6.9" H x 2.8" Dia.  I filled it
with salt water (I didn't bother with the oil layer since I was only
interested in the cap value, and the oil has no effect on that).  I
wrapped the exterior with aluminum foil to a height of 4.5", just where
the sides go from straight to curved.  I stuck a piece of stranded wire
into the water.  The length of immersed wire had no effect on the
capacitance, but it would affect the amount of losses in an actual Tesla
coil application.

I measured the value on my Wavetek 27XT multimeter, which is able to read
capacitance.  After subtracting the lead capacitance, the net result was
a capacitance of 0.57nF, or 0.00057uF, or 570pF, per bottle.

Still no idea to what voltage one bottle is good for though.

Gary Lau
Waltham, MA USA