RE: circuit board caps

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

Original poster: "Chris Sartler by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Chris.Sartler-at-adicon-dot-com>

Polytetrafluoroethylene:

Electrical Resistivity, Ohm-cm
 1E+18
 ASTM D257
 1E+18 Ohm-cm 
Dielectric Constant
 2.1
 ASTM D150; 60 Hz to 2 GHz
 2.1  
Dielectric Constant, Low Frequency
 2.1
 ASTM D 150; 60 Hz to 2 GHz
 2.1  
Dielectric Strength, kV/mm
 60
 ASTM D149
 1,524 kV/in 
Dissipation Factor
 0.0003
 Lower Limit; ASTM D 150; 60 Hz to 2 GHz
 0.0003  
Dissipation Factor, Low Frequency
 0.0003
 Lower Limit; ASTM D 150; 60 Hz to 2 GHz
 0.0003  

This assumes pure/virgin substance. Typically CB material will olny have a
resistance of 1E+15 Ohms/cm and as it is poluted the dielectric strength
goes down also.  Also note the Dielectric constant is olny 2.1, so you will
need more plates than with say Vinyl or Polyethelene ---> C= e(A/d)

, 
Chris



-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, September 28, 2001 4:05 PM
To: tesla-at-pupman-dot-com
Subject: circuit board caps


Original poster: "Janet Johnson by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jpjmassage-at-earthlink-dot-net>

Hi,
Does anyone have an idea of what the dielectric breakdown voltage of PTFE or
other circuit board materials might be?  I asked a question about this a
while
ago and then didn't consider it much further but we have a bunch of 10 to 30
mil thick, 2x3 foot sheets of sample material at work that we haven't used
for
years.  If the dielectric could handle the voltage I think it would make a
viable tank cap.  You'd probably still want to encase it in oil and remove
the
air though.  BTW how could you make a good vacuum seal?  Thanks for any
ideas...
 
JJ - SLC