Re: Question about capacitors for coil

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: John <guipenguin@xxxxxxxxx>

Sorry for asking so many questions.... I am limited on resources and 
want to /try/ and have a good design as my first coil.

So 4" diameter and 28g wire.... 1000 turns gives me (about) 13.7 in 
height which is really squat. This should give me decent results? 
Because 14" is quite far rom what Dr. Resonance said about 24-26" 
with 30g wire....which would obviously be way more turns.....

On 10/2/06, Tesla list <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: "Jim Mora" <<mailto:jmora@xxxxxxxxxxx>jmora@xxxxxxxxxxx>

Hi John,

I remember a list member from several years ago, from Denmark, stating that
the suggested windings of the aspect ratio be changed to err on the high
side - the original theory of wavelength somewhat discarded.  The repeated
theme I have seen here - is to avoid the tall, skinny coils, and favor the
shorter, fatter coils. However, there needs to be a qualification in this
reader's mind, of the ratio of the primary winding to the secondary
windings.

The general theme seems to be to get as much inductance into the primary as
possible; of course within a prime and reasonable window.

To this goal, finer wire, more secondary windings, and a larger top hat
capacitance (which is the only easily changed variable), allows for this.
Again, within resoundable limits.

My first coil, short of 40 years ago (tall and skinny failure btw), was an
out of the gate success do to the cool, modeling software online.

Many kudos and thanks go out to the authors!

It is a fine tweak between the DC resistance of the wire and the inductance
which brings us to reactance, impedance, and phase angles. I'll leave that
to our mathematicians :-)

Toward good success,
Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Monday, October 02, 2006 1:03 PM
To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx
Subject: Re: Question about capacitors for coil

Original poster: John <<mailto:guipenguin@xxxxxxxxx>guipenguin@xxxxxxxxx>

Well I am limited to #28g wire..... so with a 4 inch diameter...what
would be a better ratio? If I go 4" Diameter and 20" winding
heigth... I am at about 1460 turns.... if I do 1:6  for a heigth of
24 I am at about 1751 turns.... and I read some where I shouldn't go
much over 1k turns....

On 10/2/06, Tesla list 
<<mailto:tesla@xxxxxxxxxx><mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: "resonance"
<<mailto:resonance@xxxxxxxxxxxx><mailto:resonance@xxxxxxxxxxxx>resonance@xxxxxxxxxxxx>



Sounds like an interesting project.  I've often wondered how the 5:1
coils work so well.  I now am convinced the energy is pumped into the
base of the coil and it is propogated up like coil in a standing wave
effect.  Seems to be the only explanation when a coil has a base very
low to the concrete floor or has a large nst case under
it.  Otherwise the mag field would be distorted or shorted by all the
nearby metal.  In the case of the nst this is connected directly to
ground which would make matters worse.

Dr. Resonance
----- Original Message ----- From: "Tesla list"
<<mailto:tesla@xxxxxxxxxx> <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
To: <<mailto:tesla@xxxxxxxxxx><mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
Sent: Monday, October 02, 2006 2:41 AM
Subject: Re: Question about capacitors for coil


  >Original poster: "Gerry  Reynolds" <
<mailto:gerryreynolds@xxxxxxxxxxxxx><mailto:gerryreynolds@xxxxxxxxxxxxx>gerryreynolds@xxxxxxxxxxxxx  
>
  >
  >Hi DC,
  >
  >I've been thinking that the relationship of inductance to number of
  >turns squared has a lot of error in it for tall skinny coils.  I
  >believe the equation of:
  >
  >L = uo*N^2*Area / length
  >
  >assumes that the coupling from each turn on the solenoid is 100%
  >into all the other turns so that the total flux thru any one turn is
  >proportional to the number of turns.  For a very short and very fat
  >coil, I believe this relationship would be close.  For TC
  >secondaries with H/D ratio of say 5:1, there is a lot of error in
  >the number_of_turns squared relationship.  I bet the real exponent
  >is between 1 and 2 for typical TC geometries.  I might try to plot
  >this using JavaTC and see if there is an effective exponent given H/D.
  >
  >Gerry R.
  >
  >>Original poster: "resonance" <
<mailto:resonance@xxxxxxxxxxxx><mailto:resonance@xxxxxxxxxxxx>resonance@xxxxxxxxxxxx>
  >>
  >>Also, inductance varies as the square of the number of turns, so
  >>you want a lot of turns on the sec.
  >
  >
  >
  >