[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [TCML] Negative bias in a VTTC



Hi Vladi, I urge you to view my VTTC on youtube (big VTTC). I posted some
video of it running, along with o'scope pictures and Spectrum Analyzer
pictures. You have got to hit the tube's grid hard enough to completely turn
it off. On a low mu power triode, this generally takes several thousand
volts negative. Low mu tubes are generally better for Tesla coils. You also
need to have enough primary turns to properly load the tube. Too few turns
causes the tube to run hot. Around 25-30 turns of primary is a good start.
Then match the primary capacitor. The tickler winding needs to be a few
turns less. The grid leak resistor controls the current through the tube.
Monitor the cathode current and set accordingly. James

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Vladimiro Mazzilli
Sent: Wednesday, September 22, 2010 10:44 AM
To: tesla@xxxxxxxxxx
Subject: [TCML] Negative bias in a VTTC

Hi all.
A friend of mine have problem with  grid leak network of a single 833 VTTC.
He started with a 5k resistor and have increased its value reaching over
25k, but with a MOT without doubler, he has always the plate very red.
I noted that triodes have different plate current value with 0V biased grid
independently from the power of the tube: 811A is very simple to bias at 0V
because the plate at 2000V reach only 20mA of plate current from the curves,
otherwise 833 drain 500mA from plate, with grid  biased at 0V and with 2000V
on plate.

Had anyone made test with grid leak resistor connected at a variable dc or
'in phase' ac and grid leak capacitor grounded?

Cheers

Vladi

________________________________



Vladimiro Mazzilli

Ricerca & Sviluppo
Aros
Via Somalia 20
20032 Cormano (MI)
Tel. +39 02 66327266 - Fax. +39 02 66327528
Skype Id: - VoIp:
E-mail: V.Mazzilli@xxxxxxx
Web: www.aros.it<http://www.aros.it>
 
----------------------------------------------------------------------------
-------------------------
Per favore non stampare questo messaggio se proprio non ? necessario
Please consider the environment before printing this e-mail
----------------------------------------------------------------------------
-------------------------
Chi riceve il presente  messaggio e` tenuto a verificare se lo stesso non
gli sia pervenuto per  errore.  In tal caso e` pregato di avvisare
immediatamente il mittente  e,  tenuto  conto  delle  responsabilita`
connesse  all'indebito utilizzo e/o  divulgazione  del  messaggio  e/o
delle  informazioni  in esso contenute,  voglia  cancellare  l'originale  e
distruggere  le varie copie  o stampe.

The receiver  of this message is required to check if  he/she has received
it erroneously.  If  so,  the  receiver  is  requested to immediately inform
the sender and - in consideration of the responsibilities  arising from
undue use and/or disclosure of the message  and/or  the information
contained therein - destroy the original message and any copy or printout
thereof.



_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla