Re: Rectifier Question

Posted by Tre' (P) on December 31, 2005 at 09:11:15

In Reply to: Rectifier Question posted by jec@afo.net on December 30, 2005 at 19:43:35:

How does the voltage vary at the plate of an amplifying tube?
Why, if we have a cathode bias resistor on a 12ax7, is there voltage at the top of the cathode resistor?

It's all the same thing. Tubes conduct. A triode tube represent a varying resistance. Make the resistance low enough and the tube becomes more like a piece of wire.

With 300VAC on the plate of a rectifier tube (having no grid to control the flow) and the filaments heated, why wouldn't there be voltage at the cathode? It will be pulsating DC because a tube (all tubes that is) will only conduct in one direction. With the plates of the rectifier hooked to either end of the secondary winding the voltage is going up at one plate while it's down at the other. Only the up voltage gets to conduct to the cathode. So you get a positive half wave from one plate to the cathode and then you get a positive half wave from the other plate to the cathode. (That is, the potential will be from the cathode to ground) Now you have chokes and capacitors that will smooth the pulsating DC.

Oh, maybe this is your question. The 5y3 is a direct heated tube. The filament and the cathode are one in the same.

Tre'
Have Fun and Enjoy the Music
"Still working the problem"

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Follow Ups Full Thread

Topic - Rectifier Question - jec@afo.net 19:43:35 12/30/05 (24)

Gee, what's next, politics? Isn't .... - Russ57 14:38:50 12/31/05 (1)

Re: Gee, what's next, politics? Isn't .... - Jimmy 15:16:59 12/31/05 (0)

Re: Rectifier Question - JJ Triode 12:15:49 12/31/05 (0)

An explanation from an Intelligent Design perspective. - Jim Doyle 10:54:00 12/31/05 (8)

So god was a mathematician? - Mark Kelly 21:23:54 12/31/05 (0)

only a fool makes jokes about God - Joel Tunnah 11:22:47 12/31/05 (6)

Re: only a fool makes jokes about God - MIchael Samra 14:34:13 12/31/05 (0)

Re: only a fool makes jokes about God - pedroskova 14:13:17 12/31/05 (0)

Re: only a fool makes jokes about God - BBeck 12:53:43 12/31/05 (0)

Can we make a distinction between God and Creationism? - BofService 12:20:16 12/31/05 (2)

Re: Can we make a distinction between God and Creationism? - BillyJack 14:29:02 12/31/05 (1)

How about fear of knowledge? - Ray Moth 15:58:54 01/02/06 (0)

Re: Rectifier Question - Tre' 09:11:15 12/31/05 (0)

Re: Rectifier Question - Eli Duttman 06:08:13 12/31/05 (0)

Re: Rectifier Question - Tom Bavis 20:02:24 12/30/05 (9)

Re: Rectifier Question - jec@afo.net 03:42:52 12/31/05 (8)

Voltage drop - Mark Kelly 06:14:15 12/31/05 (0)

don't be lazy! - Joel Tunnah 05:29:11 12/31/05 (6)

don't be insulting! - BBeck 10:43:32 12/31/05 (2)

you must be joking? - Joel Tunnah 11:43:12 12/31/05 (1)

Can't we just get along? - Sugardawg34 12:37:22 12/31/05 (0)

Nothing to do with lazy! - jec@afo.net 05:37:02 12/31/05 (2)

Tom gave you the answer but maybe you didn't understand - Russ57 06:24:43 12/31/05 (1)

Thanks all! - jec@afo.net 06:39:56 12/31/05 (0)

Follow Ups

Re: Rectifier Question - Tre' 09:11:15 12/31/05 (0)

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