Re: capacitor noob question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>


----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, March 20, 2005 7:20 AM
Subject: capacitor noob question


> Original poster: Devon Ferns <dferns@xxxxxxxxxxxx>
>
> I'm about ready to build my first coil now.  I've talked with a guy that
> has built a few coils before and he suggested using a neon transformer
that
> is used to power those neon lights underneath cars.  I'm not sure what the
> voltage output of these are yet but say 10kV or something.

Nope.. those are inverter type HV power supplies, and won't work.  You need
the big old iron core type neon sign transformer.


> He also suggested I go searching for a bunch of used disposable cameras to
> get the capacitors out of them.  They are rated at around 350V or so with
> 50uF.

Those are about the farthest from what you need.  You want small
capacitance, high voltage types that can take a lot of current.  Those
little electrolytic photoflash caps are designed to store a bunch of energy
over many seconds, and dump it in a flash. TC caps need to store and dump in
microseconds.


> This made me wonder about the voltage rating.  Is it fine to string say 29
> or 30 of those together to get up to 10kV rating? How do you go about
> setting up the capacitors?  I think that the capacitance of these isn't
> exactly right for what I need anyways but I'm more concerned with the
> voltage ratings.  If I hooked up 1 350V cap to 10kV wouldn't it just blow
> to bits?

Yes... it would explode.

>
> The highest rated cap I could find was only 2.5kV at 2.2nF which for the
> size of the coil I want to make is about what I need, but not the correct
> voltage rating.

2000-2500 V is about right.  2.2nF is quite small.  You can find .15 uF (150
nF), so that when you string 10 in series, you get 20kV rating and 15 nF.

The "right" caps for this run about $2-3 each.

>
> Thanks
> Devon.
>
>