Re: First VTTC light, and a few questions

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 7/25/00 6:41:51 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Actually, I wired a MOT in to see what would happen. I can't get as long
>  of sparks off of the same voltage, but, I can increase the voltage way
>  above that and get decet operation, with the plate reddening just a
>  little. Do you think I could safley run the tube (rated at 1500V) off of
>  a 2200V MOT? I usually don't turn the variac up past 70% ( it is scaled
>  to 100, rather than a voltage scale), but the arcs are nice and long (4")
>  when i max it out. The grid voltage is okay then as well as the plate
>  current. 

Grayson,

Yes, the tube should withstand 2200VAC from the MOT.  Most folks
over-volt their tubes in their tube coils.  I often use 4000 volts ac on
tubes that are rated for 1200 volts, but not all tube types will withstand 
this extreme abuse.
>  
>   I've never used 811A's myself, so I'm 
>  > not all that familiar with their capabilities or behavior.
>  > 
>  > Assuming you have good tube emission, another way to increase
>  > the plate current is to reduce the number of turns in the primary
>  > and use a larger cap to tune.  Higher voltage operation is more
>  > efficient though.
>  
>  And so I have seen ;-)   My friend just bought a really nice ($150)
>  webcam for his laptop...   ...would you think using it to take
>  video/stills  (it has an adjustable shutter rate, 1/50s to 1/4s!, can see
>  in near complete darkness) of this coil would be advisable? I would trust
>  it with a spark gap coil of this size, but, I know that VTTCs give off
>  more RF energy...    ...what would you do?

I have found that I can leave my computer on when my VTTC is running,
and it doesn't destroy it.  I would never do this with my spark gap TC.
I've taken photos of my 3 foot spark VTTC using a digital camera
with no problem as long as I didn't get closer than 4 feet away.  
Closer than that the camera didn't work.  You shouldn't have any
problem with a small VTTC.  I use the videocamera all the time
with no problems to videotape all my coils.  

Cheers,
John Freau

>  
>  Thanks,
>  
>  Grayson Dietrich