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Re: !Salt Water Caps and Heavy Formula's!
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: !Salt Water Caps and Heavy Formula's!
> Date: Friday, May 12, 2000 12:10 AM
>
> Original Poster: "Info Host-1" <Info-at-host-1.freeserve.co.uk>
>
> Hi,
>
> I was on CO2 Laser Growers previously and thought that there was a
fair
> amount of chatter on there, little did I know I'd be getting 30+ mails a
day
> when I joined this list! :^)
No lack of interest on this list.... I use it for network diagnostics...
If I don't get mail, the net must be down.
>
> Anyway, cut to the chase, does anyone know where can I find a LOAD of
> information on salt water capacitors and their manufacture? I'm looking
at
> getting a hefty ~0.8uF -at- ~40Kv capacitor potted for me but I'd like to
know
> what my other options are first (Obviously for financial reasons). Any
> detailed documents would be of great use. It's for operation at very high
RF
> frequencies (I.e 80 or less nanoseconds).
80 nSec? you mean you need a self resonant frequency of 12 MHz or higher?
That's quite an order for a 0.8 uF cap, and may not be possible,
particularly for 40 kV. Pulse discharge caps from Maxwell, for instance,
in this range, have parasitic inductances of 10s of nH, putting their self
resonant frequencies in the high hundreds of kHz (20 nH, 0.8 uF is 1.25
MHz). This is the state of the art, mind you, not something home built,
and they aren't cheap.(>$1K)
Or, do you just need to generate very fast 640 Joule pulses (80 nSec pulse
width), which you could probably get with some sort of clever Marx
generator and peaking gap scheme, or a bunch of stacked transmission lines.
640 J is a fair energy, though....
You're not likely to get even close with salt water caps (glass or plastic
dielectric). Deionized water is used as a dielectric in fast peaking
capacitors (in the few to 10's of nSec range), but they are physically
quite large (big flat plates to keep the inductance down). I seem to
recall one described in "Exploding Wires" (Plenum Press, 1959) that was
something like 4x8 feet with a 6" water dielectric, charged by a 3 turn
impulse transformer, charged from a marx.