# Re: Wire length LC derivation,

• To: tesla@xxxxxxxxxx
• Subject: Re: Wire length LC derivation,
• From: "Tesla list" <tesla@xxxxxxxxxx>
• Date: Mon, 14 Mar 2005 20:02:15 -0700
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`Original poster: Ed Phillips <evp@xxxxxxxxxxx>`

```"There are several simplifying assumptions you have made that are not
valid.
This has been well addressed in the literature at least 70 years ago, if
not
earlier."```

```	From the time of Maxwell on; I believe Lorentz did the first exact
formulation during the 1880's.  Very accurate approximate (and much
easier to use) formulae were available by 1900.```

```"1) the secondary is not an infinite solenoid in a typical tesla coil.
More
exact equations are available for various configurations (e.g. NBS
Circular
74), or one can numerically integrate the configuration."```

```	Terry has C74 in .pdf form at hotstreamer.  Interesting reading but
tedius to pick through.  There are many excellent formulae in it,
including calculation of inductance, mutual inductance, and capacitance
of many configurations.```

```"2) The self capacitance is not that of an isolated sphere. If you must
approximate, you should probably use that for a cylinder over a ground
plane. Medhurst is the standard reference for these equations.  Or, as
with inductance, you can numerically integrate."```

```	There are plenty of inductance and capacitance calculation programs on
the web, some running "on screen" in Java.  Try a google search.  There
is also a lot of good stuff on Antonio's site.```

`Ed`