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Re: Rolled PE design question



In a message dated 3/29/99 2:12:15 AM Pacific Standard Time, tesla-at-pupman-dot-com
writes:

> 
>  I am in the process of building rolled-PE caps and I
>  thought of something:
>  
>  What if you took the bottom "sheet" of PE, so that the
>  roll was stacked like this: Al, PE, AL. Then put a
>  sheet of insulater in place of the PE sheet just taken
>  away, so it would go like this: Insulater, Al, PE, Al
>  
>  Well what I'm getting at is that the only reason for
>  two PE layers in a rolled cap is so that when you roll
>  everything up, the two sheets of aluminum don't touch
>  each other.
>  
>  So my question is, could you replace the extra PE layer
>  on the bottom (could be on top) with an insulater?
>  
>  Thanks in advance, Chris.  
>  
Chris,

Yes, you could but you would end up with much less capacitance.  If you
calculate the amount of capacitance a rolled cap will produce based on the
plate area and get a value of x, the rolled cap will actually produce 2x.  If
you substitued for instance the bottom layer for a thicker insulator, you will
end up with something less than 2x.

Ed Sonderman