# JHCTES and WinTesla

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<< Original Poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>

To All -

These two programs are similar, however, when comparing them the following
should be noted.

1. Secondary Turns Per Inch (TPI) - WinTesla uses a 0.97 factor that can
cause confusion as it does not agree with the secondary turns divided by the
secondary coil length equals the TPI of the program. This causes other
parameters to vary with JHCTES. I do not believe this factor is necessary.
When making comparisons multiply the WinTesla TPI by 0.97 and enter this
slightly smaller value into the JHCTES program.

*** You are correct, this factor is there to account for wire insulation
thickness, I could change it to a variable so that you can measure your wire
thickness with and without the insulation and enter a more acurate value
(next version).

2. Secondary Coil Self Capacity - The JHCTES uses the complete Medhurst
equation. The WinTesla uses a Medhurst K factor and different equation that
gives slightly different values for this parameter. This can also cause
other parameters to change slightly.

*** I've not seen a "complete Medhurst equation"  only tables of values,
which I have generated an equation to approximate.

3. Primary Coil (Vertical Helix) - The WinTesla calculations for primary
vertical coils appears to be incorrect. They do not agree with the Wheeler
equation when the height of the coil is changed by changing the wire
spacing.

***  Hmmmmm... I'll have to look into this - could be a bug.

4. Primary Capacitor -  In WinTesla this parameter is an output. In JHCTES
this parameter is an input. This should make it easier to design the primary
circuit because you can input the capacitor capacitance that you have in
stock or can easily obtain. When you change the primary capacitor with the
JHCTES the computer will do all of the necessary calculations to keep the TC
system in tune.

*** It's kind-of an output, the way I use it is to vary the primary turns to
match your actual value, since in practice, you will probably be able to

I am forwarding a copy of this post to R. Scott Coppersmith so he can
comment on the above. I may have made a mistake because this type of program
requires coordinating over 30 variables in dozens of equations and the
number of different TUNED Tesla coil possibilities is enormous.

John H. Couture

>>

*** I don't have a non "cripple-ware" version of JHCTES, so I can't compare
them myself.  I designed WinTesla using whatever info I could get from
discussions on this list.  If there are bugs, point them out, and I will fix
them in the next version. Thanks for your input, I don't get much feedback.

*** R. Scott Coppersmith

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