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[AMPS] Screen Supplys

To: <amps@contesting.com>
Subject: [AMPS] Screen Supplys
From: measures@vc.net (Rich Measures)
Date: Wed, 19 Nov 97 07:07:45 -0800
>Rich Measures wrote:
>>>Hi
>>>
>>>I recall a recent very good article about tetrode screen supplys
>>>in QST or QEX. Cant recall which one or the issue.
>>>
>>>Anyone have that info handy
>>>
>>For small tetrodes with less than roughly 800v screens, a zener-string 
>>shunt regulator works best. 
>
>GW4FRX's measurements quoted in my article (October QEX) show that a
>zener string emphatically does NOT "work best" from the viewpoint of
>IMD!

Volts are volts.  It matters not what type of regulator they come from, 
unless the regulator is performing poorly.  
>
>> For larger tetrodes, a 723-based positive 
>>floating series pass regulator has advantages. You can find both types at:
>>http://www.vcnet.com/measures
>
>But note also that a series regulator cannot handle reverse screen
>current, which many tetrodes can generate. You MUST use a shunt resistor
>from screen to cathode, that permanently passes the maximum negative
>screen current that the tetrode can generate. ...snip...

True indeed, Mr. White.  But note that essentially the same information 
can be found in *Amplifiers* at the above URL. 
Rich---

R. L. Measures, 805-386-3734, AG6K   


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