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Re: What kinda tube?



Additional thoughts before some thread gets started on my comment
that your tube "wouldn't be the ideal choice for Tesla operation."

My thought was if you were to take an existing coil, powered by either a
NST, MOT, or pig and attempt to replace the existing spark gap with your
740L tube, this would not work.

If however you consider the specs in the design of a new coil, any
Thyratron is a good find and can be made to work.

Sorry about sending a reply before thinking. Good luck with your new
tube. Nice find.

Phil
TCBFW




Phillip D. Rembold wrote:

> Looked in two different sources :
> Tube Lore (L Sibley) 1996 and Vade-Mecum 1955
> They don't show the prefix of  " NL- "  - - - -  but . . .
> they do list both a 740 and a 740L as a Mercury / Argon Thyratron
> most common use was as a Controlled Rectifier
> Max. plate voltage : 1,000 volts
> Max. plate current : 4,000 mA
> Filament voltage : 2.5 volts
> Filament current : 16 Amps
> Pin layout :
> 1. heater
> 2. N/C
> 3. control gate
> 4. heater / cathode
> T. anode
>
> This tube will handle 4,000 Watts, but because the plate voltage is
> so low it wouldn't be the ideal choice for Tesla operation.
>
> Tesla List wrote:
>
> > Original Poster: Teslaman-at-aol-dot-com
> >
> > I have a tube, unknown specs.  It is a NL-740L mercury vapor.