Re: VTTC provisional results

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

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

Tesla list wrote:
> 
> Original poster: "Herwig Roscher by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <herwig.roscher-at-gmx.de>
> 
> Hi all,
> 
> After having finished a series of tests I would like to inform you of
> the results and , of course  :-)  , I have a few questions as well.

> I am getting a bunch of branched streamers which are
> accompanied half of their length by thick blue seams. Occational
> thick arcs to a grounded rod at a distance of 17". Should I be
> satisfied?
> 
> Measured full load values:
> Plate voltage       : 8500 Vdc
> Plate current       : 375 mA
> Screen grid voltage : 1280 Vdc
> Screen grid current : 140 mA
> Control grid voltage: 200 V
> Control grid current: 20 mA

	That's a DC input of over 3 kilowatts; seems to me you should get more
out, but then I haven't built a high-power VTTC!

> As tetrodes require high plate resistances I would like to increase
> the number of the primary turns even more. But there are some

	Slight correction.  While tetrodes and pentodes have a high plate
resistance in the linear (Class A) mode of operation, in a Class C
oscillator/amplifier the tube is driven into plate current saturation 
at the peak of the drive waveform (trough of the plate voltage) and,
triode, tetrode, or pentode is acting as a switch and plate resistance
isn't a factor.  The voltage drop across the tube is low when it is
conducting, hence the reduction in tube loss and resulting higher
efficiency associated with Class C.

Ed