Re: 4-125A, vacuum tube do's and donts

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Parpp807-at-aol-dot-com>
> 
> In a message dated 4/9/02 1:57:31 PM Central Daylight Time, tesla-at-pupman-dot-com
> writes:
> 
> > Check filament voltages.  Over driving the filament
> >   will drastically shorten its life.  Need not be
> >   fanatical about this, but check when new, and
> >   from time to time.
> >
> 
> Yes, especially thoriated tungsten filaments which must be run very
> close, 1 to 2%, of ratings so as not to exhaust the emission properties.

	Undervoltage is more serious than overvoltage, and least if you're
drawing a lot of plate current.  A few percent over voltage will reduce
the life, but probably not compared to the time you'd be likely to
operate a VTTC.

Ed