Re: VTTC Resistor Values And Transformers

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

Original poster: "Steven Ward" <srward16-at-hotmail-dot-com> 

Hi Adam

If there is one thing thats not critical in a VTTC, its the tolerance of 
the components.  The parts i list were what i had on hand.  Sure 33 ohms 
will work just fine... the original that i copied was a 25ohm part.  That 
resistor will not get very warm at all, my 20w rating is overkill.  So 
winding some 14 or 16ga wire over a round resistor doesnt sound like much 
of a task to me...  number of turns is not all to critical either, go for 
maybe 12 through 20 turns.  Its just a choke to keep really high frequency 
stuff out.

About the gridleak resistor.  At the moment, im using 3.33k as opposed to 
5k, it seemed to make some improvement.  Really, 4.7k is just fine to start 
with, or perhaps you want the flexibility that 5 1k resistor give.  Your 
coil may only want a 2k resistance there!  you wont know these things until 
you try them out.

I got my big filament transformer at Fair Radio Sales (but i imagin you are 
in the UK or somewhere in Europe?).  It was a big 20v 20a monster that i 
found i could rewire for 12v at 20a.  Then, i opened it up and removed i 
think 3 or 4 turns on the secondary for a solid 10.2v at 125vac input (it 
helps to account for the high line voltage i often have here).  Perhaps 
ebay might have some, but i remember them selling for a lot.  My 
transformer was only US$20.

Good luck!

Steve Ward


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: VTTC Resistor Values And Transformers
>Date: Mon, 08 Sep 2003 17:52:57 -0600
>
>Original poster: "Adam Horden" <ath-at-blueyonder.co.uk>
>
>Hi Guys,
>
>I have found souces for the capacitors for my VTTC but finding it
>dificult to source the resistors required. As I dont know how
>componet tolerant the circuit I am building I am after some advice.
>
>The circuit I am useing is here:
>
>http://hot-streamer-dot-com/srward16/Dual833AVTTC.htm > decription and
>parts list
>
>http://hot-streamer-dot-com/srward16/images/dual%20833A_gif.jpg > circuit
>
>R1 in the picture is 30R 20W is it possible to use 33R?
>I can get 17W 33R from rs compoents 52 pence each. Will this be fine
>for the application even tho it is 3R out? Its ceramic body so
>winding L3 over it could be a difficult task.
>
>R2 I have been told 5K work work here. I can get 1K 100W and put 5 in
>sersies. I can also get 4.7k 72W would this work?
>
>Does any one know where I can get 10V 10A transformers? I require
>two or one 10V 20A unit for the filimant supply.
>
>Thanks
>
>Adam