Re: Help...I'm having a lot of problems here...

To: tesla-at-pupman-dot-com
Subject: Re: Help...I'm having a lot of problems here...
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Thu, 18 Feb 1999 08:19:37 -0700
Approved: twf-at-verinet-dot-com

cc. Kent and Kim

Hi Kent and Kim,

> Am I looking at the proper type of cap (ceramic)?  Should I be looking at
> electrolytic caps?  The reason I ask is because I couldn't get any output
> after hooking this unit up parallel with the transformer (i.e. one lead of
> the cap to the hot and the other to the ground).  I was only able to get a
> discharge at the gap when having the cap in series between the transformer
> and the gap.  My understanding of the ceramic variety is they are not
> polarized, or doesn't this matter?

First off, the apparently working circuit is incorrect. I suspect you 
really did wire the caps in parallel with each other? 

Ceramics of any type will get hot and fail for all but the very 
shortest of runs. Electrolytics and polarized caps of any type are 
out completely. The primary circuit oscillates and subjects the caps 
to nearly 90% reversals (charges them in the opposite sense). The 
charging from the transformer does this anyway but a rectified supply 
suffers the same problem. You might have to look at saltwater 
capacitors for a cheap and quick fix in the meantime. 

     The gap should be connected across the transformer terminals, 
and the primary cap and coil connected as a series circuit from one 
gap terminal to the other. I think the general advice about shooting 
for 6 - 7 nF capacitance in the primary will give you best results 
with your transformer. Check some of the other posts out to calculate 
the final primary inductance you'll need based on final primary 
capacitance and resonant frequency of the secondary.

> Also, I was told today that the output of the transformer must be rectified,
> that the output is AC and that caps will only work in DC.  Is this true?

No. There is no need to do that at all.  
 
> >The radius of curvature is far too big for the amount of primary
> >energy you are running. If you stick a metallic bump on it you should
> >get something. However, get the primary capacitor and primary coil
> >right first.
> >
> >Malcolm
> 
> I would assume you're talking of my toroid? And when you talk of a metal
> bump do you mean like a door knob (or something of the likes)?

A small lump of scrunched up aluminium foil taped to the toroid will 
do the trick. You can adjust bump size to get initial discharges and 
flatten it out as you bring the coil into tune. Correctly tuned and 
with the recommended primary capacitance you might not need it at all.

Keep trying. You'll get there.

Malcolm