[Amps] Fw: "Tubes 201" - How Vacuum Tubes Really Work

[Will Matney]

On 7/25/06 at 2:20 PM R L Measures wrote:

>On Jul 25, 2006, at 11:51 AM, Will Matney wrote:
>
>> Peter,
>>
>> Thanks! That is the very point I have been trying to get across all  
>> along! Remember, the original threads were asking about a 3-500Z  
>> with the grid resistor or fuse in G-G., or it was when I jumped in  
>> the mix There's been a lot of other tubes and circuits dragged into  
>> the discussion, but I've tried to center my comments around a  
>> 3-500Z G-G circuit. In grid driven circuits though as in receivers  
>> and transmitters, or some amps, the grid can be made to go positive  
>> for part of a cycle.
>
>If it does, there's a feculence flood.  However, the 4cx600J and  
>4cx1500B are fairly clean with up to 0.5mA of grid-I.

Agreed.


>
>> This I think Rich means also. He can correct me if I'm wrong.
>>
>> Thanks,
>>
>> Will
>>
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 7/25/06 at 8:40 PM Peter Voelpel wrote:
>>
>>> Hi Will,
>>>
>>> when the grid is kept grounded it can not become more positive  
>>> then the
>>> cathode if that is grounded and not negative biased as well,  
>>> except by RF
>>> drive on it above its choke.
>>>
>>> 73
>>> Peter
>>>
>>> -----Original Message-----
>>> From: amps-bounces at contesting.com [mailto:amps- 
>>> bounces at contesting.com] On
>>> Behalf Of Will Matney
>>>
>>> Peter,
>>>
>>> On that, I agree it's the only way to make one positive (for only  
>>> part of a
>>> cycle). Are there any other ways to make the grid positive and the  
>>> grid be
>>> at ground potential with the cathode at ground? A lot of amps  
>>> cathodes are
>>> at ground potential unless biased.
>>>
>>> Best,
>>>
>>> Will
>>>
>>>
>>>
>>> *********** REPLY SEPARATOR  ***********
>>>
>>> On 7/25/06 at 8:04 PM Peter Voelpel wrote:
>>>
>>>> Nothing is easier then that if the cathode is going/driven  
>>>> negative with
>>>> respect to ground.
>>>> Grid voltage is always measured from grid to cathode, not to ground.
>>>>
>>>> 73
>>>> Peter
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: amps-bounces at contesting.com [mailto:amps- 
>>>> bounces at contesting.com] On
>>>> Behalf Of Will Matney
>>>>
>>>> please explain how a grid becomes positive when tied to ground?
>>>>
>>>>
>>>>
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>>>
>>>
>>>
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>>
>>
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>
>R L MEASURES, AG6K. 805-386-3734
>r at somis.org