cathode follower

olvrkrg · 19th February 2004, 10:07 PM

Hello,

my question might seem somehow strange. If I would like to drive the cathode of a broadcasting tetrode tube that only allows a cathode - heater difference of 150V with lets say +/- 1000V, the heater somehow has to follow. Can this be done if I heat with accus and connect + and - of the accu through a resistor - lets say 1MOhms - with the cathode??? So all the accu would have to follow the cathode voltage. Any ideas if this could work??

Frank Berry · 20th February 2004, 08:23 AM

If the filament is "floating" (not grounded), simply connect the cathode to one end of the filament.
A resistor is not needed.

AKSA · 20th February 2004, 08:35 AM

Another option, not necessary better but certainly isolating, is to connect a high voltage n channel mosfet gate to the cathode, drain to B+ and source to filament, AND a 100K resistor to ground.

Cheers,

Hugh

olvrkrg · 21st February 2004, 10:49 PM

Does anyone know what it means for an accu to be connected with a signal +/- 1000V at cathode and anode? I only know that this would influence the electric double layer, but I can't estimate how much current I need to heave and drop the potentials. Does anyone know?

19th February 2004, 10:07 PM	#1
olvrkrg diyAudio Member Join Date: Oct 2003 Location: Duisburg	cathode follower Hello, my question might seem somehow strange. If I would like to drive the cathode of a broadcasting tetrode tube that only allows a cathode - heater difference of 150V with lets say +/- 1000V, the heater somehow has to follow. Can this be done if I heat with accus and connect + and - of the accu through a resistor - lets say 1MOhms - with the cathode??? So all the accu would have to follow the cathode voltage. Any ideas if this could work??

20th February 2004, 08:23 AM	#2
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	If the filament is "floating" (not grounded), simply connect the cathode to one end of the filament. A resistor is not needed. __________________ Frank

20th February 2004, 08:35 AM	#3
AKSA diyAudio Member Join Date: Sep 2001 Location: Melbourne, Australia	Another option, not necessary better but certainly isolating, is to connect a high voltage n channel mosfet gate to the cathode, drain to B+ and source to filament, AND a 100K resistor to ground. Cheers, Hugh __________________ Aspen Amplifiers P/L (Australia) www.aksaonline.com

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21st February 2004, 10:49 PM	#4
olvrkrg diyAudio Member Join Date: Oct 2003 Location: Duisburg	Does anyone know what it means for an accu to be connected with a signal +/- 1000V at cathode and anode? I only know that this would influence the electric double layer, but I can't estimate how much current I need to heave and drop the potentials. Does anyone know?

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