Re: sangamo cap question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

Tesla list wrote:
 >
 > Original poster: "RIAA/MPAA's Worst Nightmare" <mike.marcum-at-zoomtown-dot-com>
 >
 > I came across some Sangamo mica transmitting caps (kinda smallish for their
 > cost, $40 for .01 uF -at-8kv). What I was wondering is if the 8kv is ac or dc.
 > Also, if these could be ran at 1000bps in a dc resonant tesla coil. The
 > caps I have now are 35kv .03 uF maxwells that are on ebay all the time (not
 > sure how much life is left, bought them used), but have a 500bps max rating
 > (less power control in a dc resonant setup).

	The voltage rating is often the DC TEST voltage; permissible RF
voltages will be much lower.  If you look at the nameplate you'll
probably see maximum voltages (or currents, depending on the
manufacturer and what he was doing when it was made) for several
different frequencies.  They want to make sure you don't pass too much
current through the things!

	I have an 0.006 ufd 20 kV Sprague transmitting mica here which I've
often used in TC service.  I'd have to go and look but as a guess I'd
say it's about 7" in diameter and at least a foot long.  I have some
0.25 ufd 2500 volt Sprague capacitors (transmitting mica) which turn out
to be good for only around 100 volts at 300 kHz.

Ed