site update + filter question

• To: tesla-at-pupman-dot-com
• Subject: site update + filter question
• From: "Jan Florian Wagner" <jwagner-at-cc.hut.fi> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Sun, 23 Apr 2000 15:04:18 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi all,

in my series "small, crappy, but working", I've got some pics of my tiny
twin coil at www.hut.fi/~jwagner/tesla that might be interesting,
especially those TV flyback-like arcs. :o)

Other thing, I'd like to ask about RC filter design. I've a 3kV
50mA NST for that tiny twin TC. The tank cap is 8.5nF.

The current filter looks like this

NST side         tank side
---/\/\/\---+---/\/\/\----
            |
           === 470pF 6kV max (ceramic)
            |
---/\/\/\---+---/\/\/\----
 15kOhm power resistors

It's symmetric because the NST has no center tap and is not grounded.

Those 60 kOhm total at 3kVAC (=>50mA) shouldn't be a problem, as it is
50mA max from the NST anyway? Or?

The filter should now be a low-pass below 10kHz. Is that ok, or should
the freq be even lower?

The problem now is that once the filter is connected, there's a dramatic
performance drop (about half of streamer length), so there's probably
something wrong with that filter design?

How do you calculate the resistor values? And what wattage should they be?

many thanks,
and happy easter coiling to all :),

	Jan

--
*************************************************
 Jan Florian Wagner
 http://www.hut.fi/~jwagner

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