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

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 4/12/02 12:25:57 AM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:


>
> So you use the 4-125A tubes for VTTC's?CAn yo utell me what kinda schematic 
> is needed and how yo urun them?



Matt,

I use my standard VTTC schematic at my website for most
of my tube coils.  I just make slight changes as needed.  THis
schematic works well from 6" sparks to 24" sparks depending
on the power input.

What kinda things should I know about them and 

>
> any probs/issues?What kinda output do they output and what kinda sparklenght 
> can i expect?assuming a 4.5in -at- 11in long coil with 28awg wire~450khtz.



Tube coils are critical to tune and adjust.  They give much shorter
sparks for a given input power compared with spark gap TC's.  That's
a good size secondary.  You can just use a 9" dia. cylindrical
primary with that.  Use about 23 turns of 12awg pvc insulated wire.

A tube coil works much differently than a spark gap TC in many
ways.  No current limiting is used.  

  http:/hometown.aol-dot-com/futuret/page3.html

Click on the various tube coil links there.  A single 4-125A tube
can give about a 10" spark.  I wrote some other info a couple
weeks ago, check the archives. 

I use the equation:

    spark length = 0.5*sqrt input watts

to determine the expected spark length from a VTTC.
For example, if the input power is 1000 watts, 

     sqrt 1000 = 31.6.         31.6*0.5 = 15.8"

Cheers,
John


>
> Thank you to you all for your great help!I am now about to build my 3rd coil.
>
> Conventional,SSTC, and now VTTC!
>
> Thanks,
> MAtt
>
>