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Re: Door knob caps
Original poster: "Jonathan Peakall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jpeakall-at-mcn-dot-org>
Howdy Tracey, Jason,
You can run a coil on .005 uf caps or even less. I just demonstrated one
of my coils at the local High School this AM, and was running .0035uf
saltwater caps. Mind you this was only producing 18" or so streamers, so
most coilers *are* going to want more tank cap than that, but it does
work. (Inside at the school, filled with computers, I wasn't looking for
raw power) I have run that coil (3.5" secondary, 14" tall) on as little
as .0021 and achieved air breakout.
Tracey, consider some saltwater caps. I whipped some up for todays demo
because I like to show kids taht cool things can be made with ordinary
household items. Anyway, they perform almost or as well as the doorknob
caps that I blew up (suckers were 40kv, too!) last week. And cost much
less. They are heavy and so on, but they are cheap and take a beating. I
ran the coil for 30 mins non-stop to stress test the saltwater caps, and
they were only a little warm.
Like Jason says, post your coil specs. There are many informed people
here (myself NOT included) who can give you all sorts of help. They sure
Tesla list wrote:
> Original poster: "Jason Petrou by way of Terry Fritz
> Hi Tracey,
> > OK forgive the ignorance as I know this is a newbie question for
> > sure...I'm attempting the construction of my first coil and the particular
> > directions that I'm using call for 3 door knob caps wired in parallel for
> > total capacitance of 1500 Pico farads.
> 1500pF (or 0.015uF) is about right, possibly a bit too high but Im sure that
> an averaged sized coil would have no problems with that.
> >These are 15kv caps. In the
> > directions it says not to worry about the capacitance too much. My
> > is this: How much can I vary from that capacitance? I have found some
> > caps at 15kv. Can I use these caps? Do I need to add caps to get the
> > capacitance up around 400 pf? Or can I run less capacitance say around 200
> > pf?
> You really need more than about 500pF (0.005uF) to run any type of coil. The
> capacitance doesnt really matter (i.e. you can be 500pF out and nothing will
> happen) but you do need to get it close to the target capacitance. If you
> email; the specs of the coil you hope to build to the list then we can tell
> you exactly what capacitance we need.
> All the best,