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Re: need capacitor information



Subject:  Re: need capacitor information
  Date:  Thu, 29 May 1997 19:45:54 +0500
  From:  "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:  Tesla List <tesla-at-pupman-dot-com>


 In a message dated 97-05-26 00:07:31 EDT, MSM write:
 
> I recently found a 12kv 60ma sign transformer and I have been
> designing the tesla coil on paper.
>  
>  I have designed the primery and secondary but I need some information
>  about the primary capacitor.
>  
>  I need to know the dielectric constants and voltage resistance per mil
>  of polypropelene, polyethelyne, polystyrene. etc. so I can use the
>  capacitance formula to design the cap.
>  
>  If someone has a table with this information of can help in any other
>  way it would be much appreciated.

By voltage resistance per mil, I assume you mean dialectric strength 
or puncture voltage. Below is a copy of a table produced by Richard 
Quick some time ago.

=====================================================================
                             Dielectric strength   Puncture Voltage   
       Material                       K           per Mil(0.001 inch) 
---------------------------------------------------------------------

    Miscellaneous
    -------------
    Vacuum                            1.0
    Paper, bond                       3.0            200
    Paper, Royal Grey                 3.0            200
*   Paper, telephone, treated         2.5 - 4        200 - 250      
    Paper, Parafin Coated             2 -3.5
    Paper, Kraft                      2.2
    Oil, Castor                       4.67
    Oil, Mineral, Squibb              2.7            200
    Oil, Mineral                      2.2
*   Oil, Transformer                  2.1 - 2.5      75             
    Rubber                            3.0
*   Rubber, Hard                      3.0            160 - 500      
1   Rubber, Vulcanized                3.2 - 3.9                     
    Fibre                             5.0 - 7.5      150 - 180
    Fibre, Red                        5.0
    Mica                              4.5 - 8.0      3800 - 5600
    Mica, Ruby                        5.4            3800 - 5600
    Quartz                            3.8 - 5.0      1000
*   Quartz (Fused)                    4.2            150 - 200      
    Shellac                           2.5 - 4.0      200 - 400
    Spar Varnish                      4.8 - 5.5
    Steatite, low loss                5.8            150 - 315
    Steatites (Magnesium silicate,etc)5.5 - 7.5      200 - 300
2   Cambric (Varnished)               4.0                           
    Alsimag 196                       5.7
3   Gutta Percha                      4.0                           
4   Amber                             3.0 - 7.0                     
    Resin                             2.48 - 2.57
    Enamel                            5.1            450
    Mycalex                           7.4            250
    Silicone RTV                      3.6            550
    Wood                              2.0 - 5.2
*   Wax (Parafin)                     2.1 - 2.5      250 - 450      
    Beeswax                           2.9 - 3.0
5   Slate                             7.0                           
    Barium titanate(25 C)             1200
    Bariam titanate                   6000
    Titanium dioxide                  125
    Cellulose acetate                 3.3 - 3.9      250 - 600
6   Casein, Moulded                   6.4                           
A   Polytetraflourethylene            2.0                           
    Aluminum oxide                    8.7
    Tantalum pentoxide                22

    Glass
    -----
    Glass                             4.8 - 10       300
    Plate Glass                       6.8 - 8.4
    Pyrex Glass                       4.8 - 10       335
    Window Glass                      7.6 - 7.8      200 - 250

    Ceramics
    --------
    Cordierite ceramics               5.0 - 5.5      100
    Magnesium titanate ceramic        12 - 18        150
    Porcelain                         5.1 - 7.5      40 - 280
    Titanium dioxide ceramic          70 - 90        100
    Titanium-zirconium dioxide ceramic40 - 60        150

    Plastics
    --------
    Bakelite                          4.4 - 5.8      300
    Bakelite, Mica filled             4.7            325 - 375
    Epoxy Circuit Board               5.2            700
7   Formica                           4.6 - 4.9      450            
    Nylon (lowest values of 3 types)  3.2            407
    PVC (rigid type)                  2.95           725
    Plexiglass                        2.8            450 - 990
    Polyethylene                      2.2 - 2.3      450 - 1200
    Polycarbonate (Lexan)             2.96           400
    Polyethylene Terphthalate (Mylar) 3.0 - 3.1      7500
    Polystyrene                       2.5 - 2.6      500 - 700
    Teflon                            2.1            1000 - 2000

    Gases
    --------
    Air (dry air at 1 atm)            1.0006         30 - 70
*   Air (20 atm, 19 deg. C)           1.0108         500            
*   Carbon dioxide ( 1 atm, 0 deg. C) 1.000985       36             
    Carbon dioxide (20 atm, 15 deg. C)1.020
*   Hydrogen (1 atm,0 deg.C)          1.000264       26.1           

    Liquids
    --------
    Ammonia (liquid)                  22
    Benzene                           2.28
8   Carbon tetrachloride              2.24                          
9   Chlorinated diphenyl              6.5                           
    Ethyl Alcohol (O C)               28.4
    Ethyl alchohol (20 deg.C)         25.8
    Methyl alchohol                   33.1
    Water (distilled)                 80 - 81

LEGEND:

* = Measured in Kilovolts per centimeter. All others are Volts 
    per mil (.001 inch) unless otherwise stated.
1 = Vulcanized means it has been melted, or heated in some 
    way.
2 = Cambric is a finely woven white linen or cotton fabric.
3 = Gutta Percha is a rubbery substance made from the latex of 
    tropical trees and is used in insulation, waterproofing, 
    and dentist use it in thin sheets sometimes when working 
    on teeth.
4 = Amber is a hard, translucent, yellow, orange, or brownish yellow
    fossil resin, used in making ornamental objects like jewelry.
5 = Slate is a fine grained metamorphic rock that splits into 
    thin smooth faced layers. Black Boards for writting are 
    made of this. Also used as roofing material in some areas.
6 = Casein is a white, tasteless, oderless milk and cheese protein 
    used in the manufacture of plastics, glues, paints, and food. The 
    word 'moulded' means it has been shaped by a mold.
7 = Formica is a trademark for any of various high-pressure laminated
    plastic sheets of melamine and phenolic materials used for 
    chemical and heat-resistant surfaces.
8 = Carbon tetrachloride is a very toxic substance. It has also been
    shown to cause cancer in lab animals. It is banned in most labs. 
    It is a liquid that was used as a strong solvent.
9 = Chlorinated diphenyl is a liquid dielectric that is used to       
    impregnate Kraft paper in small A.C. capacitors. This is a PCB
    and may cause cancer, handle carefully.
A = Polytetraflourethylene films retain good properties even at 200 
    degrees Celsius (200 C).

atm = atmospheres (pressure of air at sea level is 1 atm).
deg.C = degrees Celsius.
 
Warning - Some liquids and gases listed may be explosive under the 
          right conditions. Many solids can catch fire and burn. Use 
          CAUTION and GOOD COMMON SENSE.

Note: Some books gave very different values for each substance so I
      have given you the highest and lowest values reported. The 
      values will depend on the purity of the substance your using. 
      If you know your substance is very pure then use the higher 
      value reported. If you know your substance is contaminated or 
      of poor quality then use the lower values reported. If you have 
      unknown purity then use the average of the values given.