Re: More help on caps

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: More help on caps
From: Tesla List <tesla-at-stic-dot-net>
Date: Tue, 11 Nov 1997 08:40:59 -0600
Approved: tesla-at-stic-dot-net

From:	Bert Hickman [SMTP:bert.hickman-at-aquila-dot-com]
Sent:	Tuesday, November 11, 1997 8:45 AM
To:	Tesla List
Subject:	Re: More help on caps

Tesla List wrote:
> 
> From:   Chris Fileccia [SMTP:ChaoticD-at-swbell-dot-net]
> Sent:   Tuesday, November 11, 1997 12:01 AM
> To:     tesla-at-poodle.pupman-dot-com
> Subject:        More help on caps
> 
> I have realised that I need to make my own caps for my first TC.
> But, my delema is this. I know I can't make rolled caps. So I am left with
> salt water or stacked. I have been thinking about using the bottle caps but
> I would have to use a lot of them. Especialy at 43nF a six pack wow. Not
> even close. One said to use .005 MF (5000 pF) and one said to use .03 mfd
> and .02 mfd. Either way they are far apart from each other. Win Tesla says
> the best cap to use is  0.0066uF.(That is another thing. I don't want to
> sound stupid, but I know micro as a uF, is that the same thing as a mf.
> I thought that was milli. Hmmmm.) Anyway I have read alot of material but I
> am still confused. I like the siplistity of the bottle caps, but it seems
> that they are inifecient. Plese corect me if I am wrong. I am tring to
> learn as much as I can so I don't have any major disastors.
> 
> Also I have heard many discrepencies about the stacked caps. I am running
> out of money, but I like to do things right.
> 
> "Firm beliver that education is the safest way"
> But not nessesarly proper gramer or spelling:+}

Chris,

Certainly the least expensive route will be the salt-water caps. Even
though they are inefficient, they WILL get you going and your coil will
create respectable sparks! If Win Tesla recommends 0.0066 uF, it sounds
like you may have a 12,000 30 MA neon transformer. Most of these design
aid programs try to size the cap to the HV power source impedance. While
this is important, it is very important that the primary be sized
properly so that, in combination of your tank cap, you can match the
resonant frequency of secondary and toroid. If you arbitrarily size the
secondary and primary and solve for matching resonant frequencies, you
may end up needing a tank capacitor that's too large for the transformer
you've got. This may be why you've gotten the other, higher, tank cap
values. What sizes of secodary, toroid, and primary are you thinking
about using? And what does Win Tesla indicate for these? 

BTW, units of measure for capacitance have undergone evolution over the
years, and the use of older and newer conventions can sometimes be
confusing. Typical units for capacitance and their preferred
abbreviations are:
 Farad = F
 MilliFarad = mF = 10^-3 F
 MicroFarad = uF or MF = 10^-6 F  (uF preferred)
 NanoFarad  = nF = 10^-9 F
 PicoFarad or MicromicroFarad = pF, uuF, or MMF = 10^-12 F (pF
preferred)

Safe coilin' to you!

-- Bert --