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Re: Dialetric




From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Tuesday, November 25, 1997 2:05 AM
To: 	Tesla List
Subject: 	Re: Dialetric

On Tuesday, November 18, 1997 4:39 PM Chris Fileccia
[SMTP:ChaoticD-at-swbell-dot-net] wrote;

> I have just constucted 2 beer bottle caps 
> One with Idonized salt one without. There is a diffrence. My question is
> what is the dialectric of glass. I used Red Dog bottles. It messuers .1013
> (i think that is in inches or 101.3m), if i read the micrometer right. I
> want to know the dialectric and peak votage.

Hi Chris, the problem with the dielectric characteristics of glass is that 
glass is a very variable substance! The following values were listed by 
Richard Quick some time ago:

                Dielectric   Dielectric
                 constant    strength /mill
Plate Glass     6.8 - 8.4      300
Pyrex Glass     4.8 - 10       335
Window Glass    7.6 - 7.8      200 - 250
 
The only accurate way to determine the dielectric constant of the glass you 
are using is to carefully measure the area of the plates (effective plates 
since your using salt water) and carefully measure the capacitors 
capacitance and then calculate the dielectric constant using the standard
formula to calculate a capacitors capacitance;

        0.224 x K x A
    C = -------------  x (N - 1)
              d

     C = capacitance (in picofarads)
     K = dielectric constant
     A = area of plates (in inches)
     d = seperation of plates (in inches)
     n = number of plates

To determine the glasses dielectric strength you have to keep increasing an 
applied voltage to a given thickness of the glass untill it punctures.

                               Sincerely

                                \\\|///
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                           Alfred A. Skrocki
                   Alfred.Skrocki-at-CyberNetworking-dot-com
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