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IW6DFW > TECH 02.06.06 14:43l 65 Lines 2431 Bytes #999 (0) @ WW
BID : 23672_IW6DFW
Read: DL1LCA GUEST
Subj: Re: Capacitors and Resistivity
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Sent: 060602/1500 @:IQ6TC.#AP.IMAR.ITA.EU $:23672_IW6DFW Sally 4.0.221
Date: ven, 02 giu 2006 15.00.12
From: IW6DFW (Maurizio)
To: TECH@WW
Subject: Re: Capacitors and Resistivity
From: IW6DFW@IQ6TC.#AP.IMAR.ITA.EU
VK3ABK's original message...
> I must thank Maurizio, IW6DFW, for his interesting comments....
>
> He wrote....
>
> Reading my physics books about e.m.f. I'm sure that a direct
> correspondence between dielectric constant and capacitance
> there is with certainty only when the place where is the field
> (dielectric medium) is homogeneous, so in mathematical words,
> permittivity can be treated as a constant then brings out from
> the integral operator.
> If these conditions doesn't occurs, it's necessary to use the
> linearity property of the integral operator, so split the
> formula into a run of sums of a number of addendums equal to
> the number of interphaces between inhomogeneous materials. In
> this way no direct proportionality is insured.
> I hope I've been clear.
>
> Yes, Maurizio, that's perfectly clear, and would be important
> with many dielectrics. Years ago, I dealt with some most
> inhomogenious dielectrics! In my comments, I tried to
> understand the reason for using the square root of the
> dielectric constant (or permittivity if quoted) in (circular)
> coax cable. We don't always get an explanation for equations
> and constants used in text books. I proposed my own thoughts
> and reasoning.
>
Thankyou very much VK3ABK for the reply.
I agree with you about improvised technical authors, so "I got the word" (this is a literal
translation of Italian slang, I hope it's an english way to say too!) only because I've spent
about seven months experimenting with full customs dielectric liquids level sensors
finalized to my thesis of degree... Unfortunately this interesting topic is well resumed only
in italian language with a pdf of about 300 pages. It's rich of images, formulas and
experimental data, so if you are interesting you could download it from my internet home
page in the HW section (Patternator project for Porsche e Siemens VDO Automotive).
73 Ciao a tutti , Maurizio,
Sound card with homebrewed DIGI_VOX interface!
DIGI_VOX is personal project of mine. Info at:
E-mail: iw6dfw@gmail.com
Home page: http://digilander.iol.it/mauxxx1
IP:44.134.243.10
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Timed Tuesday 11 January 2005 16:26 gmt
BBS IW6DFW@IQ6TC.#AP.IMAR.ITA.EU
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