Re: Sword-like VTTC spark pix (ceramic tube questions)

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <cwillis-at-guilford.edu>


 

Hey Brian, 

Good point about the downsides of these ceramic tubes.  I was under the
impression, though, that their electrode structures permitted them to be
conditioned for very high voltage use.  The 833-A, my favorite glass tube
for economy and power, can only (ha!) be used up to 6 kV or so, but I
recall hearing that some of the ceramics can undergo a special burn-in
procedure that dramatically increases their flashover ratings.  (Does it
have to do with a cylindrical electrode structure?)  This would make them
especially suited to VT Tesla coils, which from my experience and I think
that of others, do best with a high plate voltage and high L to C tank
ratio.  Do you know if the ceramics have any particular tendency to have
strong parasitics over glass tubes?  I've never used VHF suppressors on
tube coils, but then these tubes (like 833-A) have much lower gain at VHF
than most ceramics.  Thanks for the comments.

Carl

>Hi, the only advice for ceramic tubes -vrs- glass is 2 things: 1 use the
>correct tube base with cooling,2 start out at low power until you are sure
>there are no parasitics and tuned up. ceramic are hi-power for their size
>but without good tuning and the right amount of air cooling they go PUFF
>real easy. cul brian