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813 tube coil
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From: Scott MacGregor [SMTP:smacgregor-at-aasp-dot-net]
Sent: Monday, June 01, 1998 9:40 AM
To: Tesla List
Subject: Re: 813 tube coil
Tesla List wrote:
>
> ----------
> From: Alan Sharp [SMTP:AlanSharp-at-compuserve-dot-com]
> Sent: Saturday, May 30, 1998 5:46 PM
> To: Tesla List
> Subject: 813 tube coil
>
> Greetings All,
>
> At the UK Teslathon I bought a couple of 813 valves -
> Has anyone used these for a tube coil? - is there a good
> schematic out there?
>
> I've never used tubes before - I think they need a heater -
> will a bunsen burner be all right :)
>
> I have checked out the specs 2.5kV, at 225mA - so in
> theory a pair of these - and a 2.2kV microwave transformer
> and I should be able to shoot for 1kw power output.
> But they are pentodes (and I only understand triodes)
>
> The filament needs 10V at 5A - can I simply connect
> a 5-0-5V transformer or do I need to have a way of
> adjusting and correcting the current?
You provide 10V to the pins, and the filament resistance will limit the
current to 5 amps. A good way to increase the life of your tubes would
be to use a 5 amp variac to provide heater power. Increase the voltage
to the tube slowly till you reach 10 volts. This prevents "shocking" the
filament with a sudden inrush of current.
> Hints, tips, help greatly appreciated.
>
> Have fun,
>
> Alan Sharp UK
--
Regards,
Scott MacGregor EES,Co.
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Enterprise Engineering Services Co.
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