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Dielectrics




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From:  Bob Schumann [SMTP:tesla-at-america-dot-com]
Sent:  Thursday, March 26, 1998 1:10 AM
To:  Tesla List
Subject:  Re: Dielectrics

At 12:45 AM 3/26/98 -0600, you wrote:
>
>----------
>From:  Justin Oliver [SMTP:joelec1-at-ozemail-dot-com.au]
>Sent:  Wednesday, March 25, 1998 4:09 PM
>To:  tesla-at-pupman-dot-com
>Subject:  Dielectrics
>
>Would it be okay to use some polystyrene as a dielectric in a stacked plate
>cap as I can get a heap of sheets of this stuff for free. It is about 1cm
thick.
>Also, does it matter how big the dielectric is. Can you make a 100Kv cap and
>then use it on 10Kv?
>Thanks in advance,
>Justin

Justin,
	I believe polystyrene would be okay. 1cm is about .4 inches which
	can withstand quite a bit of voltage. I would guess about 40kv
	easily. Making a cap rated for 100kv and then using it on 10kv
	is fine and I would say desirable. As a rule of thumb, I like to
	use caps that have a 'minimum' rating of twice the voltage that
	I plan to use in my circuit. The energy from the secondary circuit
	can and does 'swing' back into the primary circuit which makes
	an overated cap the best choice. One thing to keep in mind is that
	the further the plates are from each other (dielectric thickness),
	the lower the capacitance. You may have to really stack up some
	plates to get to a desired capacitance. Hope this helps.

	Bob Schumann