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Re: Bypass Caps

tesla-at-grendel.objinc-dot-com On Mon, 18 Mar 1996 20:00:59 +0700, you
wrote:

>>From DELCOKEVIN-at-aol-dot-com Mon Mar 18 13:15 MST 1996
>From: DELCOKEVIN-at-aol-dot-com
>>Received: from emout06.mail.aol-dot-com (emout06.mail.aol-dot-com [198.81.10.43]) by uucp-1.csn-dot-net (8.6.12/8.6.12) with ESMTP id MAA26549 for <tesla-at-grendel.objinc-dot-com>; Mon, 18 Mar 1996 12:59:15 -0700
>Date: Mon, 18 Mar 1996 14:58:42 -0500
>To: tesla-at-grendel.objinc-dot-com
>Subject: Re:Bypass Caps
>
>Does anyone have a good source for small (.001uf 20kvac) bypass caps?
>I have blown up too many neons, and I do not want to blow another.
>
>    Kevin M. Conkey
>
>
1. 	roll your own. 500pF is 3" by 10" plates with 0.04" PVC (from
hardware supply store for drain pans)

2.	Use about 2.5K ohms 100W series resistor between the RFI choke
and the bypass cap to damp the LC resonance fo the filter network.

>How do I select a bypass cap value?

It's not a "hard" science yet. Increasing the value will decrease the
RFI on the neon but increase the current loss from the neon through
it. 500pf at 60Hz => 5.3 megohms. at 7.5KV about 1.4 milliamps. 1000pF
would shunt twice the current. I've had good luck in the last (2
WEEKs) with a 2.25K ohm resistor ( 8 watts per leg) to dampen the
resonant rise fo the RFI network. I used a 9K adjustable resistor,
ends in parallel, center taped for this value.

While this wastes some power, I feel that the protection it provides
is worth it for us hobbyists coilers

	jim.