RE: Question about capacitors for coil

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Cameron B. Prince" <cplists@xxxxxxxxxx>

Hi John,

The problem with using these caps in a disruptive coil is that the silver
plating that makes up each plate is gradually destroyed over time. As this
happens, the capacity drops and you have to continually adjust your primary
tap to compensate. I think others will agree that you'd be better off with
an MMC cap.

Good luck,
Cameron

> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Sunday, October 01, 2006 7:27 AM
> To: tesla@xxxxxxxxxx
> Subject: Question about capacitors for coil
>
> Original poster: John <guipenguin@xxxxxxxxx>
>
> Hello.
>
> For my 9kv @ 30ma AC transformer, I will need a capacitance of about
> 0.0088 MFD. I have been looking at some 40kv 2000pf Strontium
> Titanate ceramic caps on ebay. These have a "DC" voltage rating of
> 40KV.  I have been told that I can de-rate this rating to around
> 40-50% min for use with a High voltage AC circuit.
>
> Would these be an OK choice in parallel to give as close as possible
> to 0.0088uF? I am fairly new to coiling and would like an opinion
> before I buy these caps.
>
> Thanks.