# RE: Formulas

```Original poster: "David Dean by way of Terry Fritz <twftesla-at-uswest-dot-net>" <deano-at-corridor-dot-net>

Hi Jason,

I just put a lookup table with some wire sizes from a wire table and the
following formula for max TPI
=1/(J13*1.05)
in the output cell, and the lookup function in cell J13
= VLOOKUP(F9,A242:B250,2)
F9 is the input cell where you put the gauge of the wire you want to
calculate for,
and the lookup table has the following info in it.

Wire size table
Row     Column
A       B
242   18	   0.0437
243   20       0.0346
244   22       0.0276
245   24       0.0223
246   26	   0.0178
247   28	   0.0144
248   32	   0.0095
249   36	   0.006
250   40	   0.0038

Of course you might want to have more sizes. These diameters are for heavy
build magnet wire and come from WireTron.  Any wire table will do, but be
aware that the thickness of the insulation will vary from manufacturer to
manufacturer a bit.

later
deano

> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Thursday, February 15, 2001 12:36 PM
> To: tesla-at-pupman-dot-com
> Subject: Formulas
>
>
> Original poster: "Jason Johnson by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>
>
> Does anyone have a formula for calculating the AWG size of a wire from the
> diameter (preferably in inches), and/or a formula for the number
> of turns per
> inch based upon the AWG? I need these formulas for an excel
> simpler they are the easier it is for me to put them in. They need to have
> fairly good accuracy (+/- 1% or less). Also I haven't really
> looked around for
> them yet, but if anyone has any formulas for inverse conical
> (saucer shaped)
> primaries I could use those too.
>
> Jason Johnson
>
>
>

```