Re: R.A. Ford (book)?(update)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "ebyng by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ebyng-at-netlimit-dot-com>

Wait a min.......

Ok, heres the problem with that........

The actual chapter/quote is :

Assume that the target frequency = 400 kilocycles

Using the formulas for the L-C values, 400 Kcycles has a value of 0.1583
for the product L-C where L is in microhenries and C is in microfarads.....
the inductance L in microhenries is approx given as
L= a2nd x n2nd/8a + 11w
where W = width of coil
A = average radius in inches as measured from the middle of the primary to
the center of the secondary.
N = number of turns in the primary coil.......

then, if L = 61.5 microhenries

C = 0.1583/61.5 

and C will = 0.0026 microfarads.


Okayyy, so thats the reprint, cut into small sections.

so what he's trying to do is find capacitance that will create a frequency
of about 400 Kc.

So if your solving to find capacitance, you cant use 
wavelength=1884 x sqrt(LC)   freq=300,000,000/wavelength (in meters), L in
microhenries, C in microfarads.

because you dont have a specific capacitance(yet).

I can see how you would reverse engineer this to find the frequency that
your coil is running at, but how does this way work???
Thanks
S

  
----------------------------------------------
Original Message
From: "Tesla list"<tesla-at-pupman-dot-com>
Subject: Re: R.A. Ford (book)?
Date: Wed, 14 Mar 2001 11:52:19 -0700

>Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<jimlux-at-earthlink-dot-net>
>
>
>> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
><Mddeming-at-aol-dot-com>
>>
>> In a message dated 3/14/01 12:49:47 AM Eastern Standard Time,
>> tesla-at-pupman-dot-com writes:
>> >
>> > Anyway. I would love to get my hands on that table, to see if that
>works.
>> > He's calculating a coil to run on a specific frequency in that chapter.
>> >
>> > If anyone has that book or that table, could I get a scan. copy. email
>> > whatever of it??
>> >
>>
>>
>>
>> CRC 34th Ed. is from 1952. In the 36th edition (1954) the table is on
>pages
>> 2973-75. By 1974 the table had been dropped from the handbook since by
>then
>> any 5-function calculator could reproduce the data. The table does not
>give
>> specific values for L  and C, but only for the product ( L x C) You can
>> generate this table in any spreadsheet using the same formula they did:
>> wavelength=1884 x sqrt(LC)   freq=300,000,000/wavelength (in meters), L
in
>> microhenries, C in microfarads.
>>
>
>Just to be a bit picky.. If you are using Excel, you can get better
>computational precision (and what's more important, eliminate some "magic
>constants") by doing:
>
>Frequency = 1/( 2 * PI() * sqrt(L * C))
>
>
>
>
>
>

_____________________________________________
Free email with personality! Over 200 domains!
http://www.MyOwnEmail-dot-com