RE- Cap setup suggestion
From: Robert Michaels[SMTP:robert.michaels-at-online.sme-dot-org]
Sent: Friday, June 20, 1997 2:38 AM
Subject: RE- Cap setup suggestion
T>From: Brandon Doughan[SMTP:fiveht-at-well-dot-com]
T>Hey you HV freaks-
T> I was lucky enough to get ahold of 20 or so doorknob caps rated
T>at 30KV and 3600 pF (.0036MFD). I'm wondering about a few things:
T>multiplier device]. On one end of the cap pairs (I've scrapped the
T>rubber off a few) there is a resistor. I don't know the value. My
T>question is, if I use several pair in a coil powered by a 15KV NST, how
T>will these resistors affect my capacitance? It would be nice to keep
The resistors won't affect capacitance a twit. They may
affect damn-near everything else:
What is the resistance value of the resistors?
How are they wired to the capacitors - series,
T>the added insulation of the rubber (and not have to scrap all of it
T>off!), but if the resistance is negatively affecting my coil output, as I
T>suspect, then I'm gonna have to do it.
Don't scrape then, dissolve it (that's the = solution = )
T> Second question- I know you want to have your caps rated 3
T>times your primary voltage, but I want to get away with just have my 30KV
T>caps with my 15 KV NST. Anyone have experience with doorknob cap
T>failure? Think I can do it?
On voltage -- you might squeak by.
On the use of doorknob capacitors -- to the extent they are
useable at all in Tesla coils, they are useable intermittently
= at best =.
Doorknob capacitors are for dc service, not ac --
and certainly not high-frequency ac -- and certainly
not high-frequency Tesla ac.
Use them on a very low duty cycle (say 10 - 15 %) and they
may serve well enough for you to get your feet wet in Tesla
coiling. That's what's important.
You can spend the required $500 - $600 (US) on
a proper capacitor later. Or make your own --
Dr. Tesla did.
T> Last question- I cracked one of these caps open and found that T>it
consists of just two plates each no more than 3 sq. ins. and about an
T>inch of that strange ceramic dielectric. How do these get .0036MFD??
T>This must be because of the K value of that stuff. This amazes me.
It's that strange ceramic dielectric, barium titanate in
all likelihood. Amazing, isn't it.
T>Thanks for your help_ Brandon
T>PS- Visit the High Voltage Camp at Burningman '97!
All right, all right! You've got all of our collective
attention now: What is it?
High-voltage camper, in --