Re: Mini VTTC--Possible tubes?

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

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


Matt,

Any of the "sweep" tubes from televisions are useful for the very smallest
tube coils.  Mark Reszotarsky (sp?) has a schematic on pupman-dot-com for one
such beam-tube tesla coil.  My website at
www.angelfire-dot-com/electronic/cwillis also details such a tesla coil, using
a minimum of parts, in the context of a "plasma tweeter."  You won't get
much spark out of these little coils, but they are very cheap to build-
they even lack a traditional primary tank circuit, and you end up needing
only a source of plate voltage, filament power, a small RF choke, a small
"secondary" coil, and a grid-bias resistor.

The 811-a triode is a good starting point for many builders.  They used to
be available for $10 from RFparts-dot-com, but I think the prices have gone up
a bit.

Essentially any glass triode makes a good tube to start with.  More grids
means you have to figure out a little more, and they can be a nuissance to
deal with.  Glass tubes are recommended over ceramic ones, in my opinion.
For one thing, the sockets are easier to come by.  I have two medium-sized
glass triodes on eBay right now, item 1710445087.  They have no number but
are ideal for tube coils since I have used them for that purpose.  It
shouldn't be hard to find a plethora of potentially great tubes.

Good luck.

Carl Willis