Re: [TCML] Chinese made polystyrene caps

[mddeming@xxxxxxx]

Hi Dave,

I have not used these, so my observations should be weighted accordingly. I noticed that while they gave a good deal of information, almost none of it was relevant to capacitor performance: no ESR, no pulse rating, no peak current data, no voltage reversal data, etc. The physical size makes me cautious about their power-handling capabilities. They say "Experience keeps a dear school", and at $180/pop, this poor boy can't afford to stress-test a statistically significant sample of them. I would recommend waiting until some of our more "affluent professionals" buy and?blow up a dozen or so. ;^))) 

Matt D.


-----Original Message-----
From: David Rieben <drieben@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Tue, 12 May 2009 8:47 am
Subject: [TCML] Chinese made polystyrene caps



Hey guys,

I was just wondering if anyone has any experience
with these Chinese made capacitor types that are
absolutely flooding eBay these days:

http://cgi.ebay.com/30kV-0-2-F-High-Voltage-Polystyrene-capacitor-HAM-audio_W0QQitemZ360120565659QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item53d8dbbf9b&_trksid=p4634.c0.m14.l1262&_trkparms=%7C301%3A1%7C293%3A6%7C294%3A30

My guess is that since this particular one is only
80 mm x 120 mm long or appr. 3 1/8" x 6" long, 
and yet it has a very significant energy capacity (90 J), 
there is no way that its internal construction could 
render it competant to withstand the high RMS cur-
rents and tremendous peak currents encountered
in larger SG driven Tesla coil circuits, even though 
polystyrene is a good, low loss dielectric. Likely of 
very fragile metallized film construction. What are
your thoughts?

David Rieben
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