Re: inductance calculations (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: List moderator <mod1@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 21 May 2007 20:52:55 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: inductance calculations (fwd)

At 03:57 PM 5/21/2007, you wrote:
>Original poster: List moderator <mod1@xxxxxxxxxx>
>
>Hi Wyatt, Ron, All,
>
>IF you are old enough, or have done enough research, there IS a direct
>conversion, as used in early electrical work. Tesla used these terms 
>in CSN and  in
>many of his patents.
>
>AS USED BY TESLA: 1 cm of inductance is 1 nH of inductance.
>AS USED BY TESLA: 1 cm of capacitance is 1.111... pF of capacitance
>
>The derivation for this is, I believe, somewhere  in  the list archives.
>
>
>Hope this helps,
>
>Matt D.
>Oldfart & occasional student of electrotrivia."
>
>      It's interesting that Tesla used both in his CSN and seemed to 
> switch back and forth arbitrarily.  Can't remember if the 
> conversion above refers to the esu or the emu system of units.  I 
> have a couple of pre-1900 text books which use both as well as 
> "practical units".  Tesla lived in changing times and in some ways 
> adapted well and in others not so well............
>
>Ed

Same kind of thing crops up when reading papers from the 19th century 
and earlier (e.g. Paschen's paper in Annalen der Physik): all manner 
of "standard units" which I'm sure were in common use at the time the 
paper was published, but have since been lost to the mists of time. 
(or, were based on some standard measuring instrument.. much like the 
Richter scale is based on deflections in mm on a specific kind of 
seismograph recorder or astronomical magnitudes, etc.)