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RE: Caps
Hi Scott/all,
I have used door-knob caps in small TC's (<100w) with some
success,
It all seems to depend on the type you use.
Different ones have different types of ceramic dielectric, with varying
results.
The ones I used were made by LCC, type HT0 and HTD, which both gave good
results.
You have to be careful not to push them to hard though.
I have a 3000pF 20KV HT0 in a little 50w demo coil that has been used
regularly for years with a 4kv transformer.
It shows no sign of heating, but from my experience, once ceramic caps do
start to show signs of heating, they usually fail soon after.
I have seen at least one coilers web site that has a bank of doorknobs
driving a 1KW coil with big sparks, though most people go for less fragile,
plastic dielectric caps at high powers.
The cost of new doorknobs would be prohibitively expensive, but they can
usually be found surplus at Hamfests at reasonable prices.
This is where I found most of mine, here in the UK.
Cheers Martin Dale Nottingham
> ----------
> From: Tesla List[SMTP:tesla-at-pupman-dot-com]
> Sent: Tuesday, April 27, 1999 11:52PM
> To: tesla-at-pupman-dot-com
> Subject: Caps
>
> Original Poster: Scott Harris <srharris-at-Princeton.EDU>
>
> Nobody answered my questions, so I'll ask again.
>
> Doorknob caps: How suitable are they for a NST powered Tesla coil?
>
> Do HV ceramic caps work poorly, or not at all?
>
> Does anybody know of good commercial sources for new and/or surplus HV
> caps.
>
> -Scott
>