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[AMPS] Screen regulation

To: <amps@contesting.com>
Subject: [AMPS] Screen regulation
From: measures@vc.net (Rich Measures)
Date: Sun, 6 Dec 1998 09:14:46 -0800
>
>OK guys, I started a long series of posts with my last question about
>regulating a 1KV screen supply for a 4-1000 in AB1.   I've tried a lot of
>your ideas, but mostly have turned a handful of sand-state stuff into
>puddles of silicon.
>
>The screen supply itself is overkill, it's easily capable of 500W
>continuous, resonated choke input.
>
>To make a long story short, I think my supply may be stiff enough. I don't
>have access to fancy test equipment so I'm just looking for your thoughts on
>this.   The supply is heavily loaded (6K ohm bleeder). When I add an
>additional 6K bleed (160ma load) I get a 50V drop (1000 -> 950).  Clearly
>this is not any kind of a dynamic load.  On the plus side, the variac I'm
>using for testing is a pretty wimpy job. In the final installation I'll be
>using a much huskier variac and the primary side will be stiffer running the
>transformer on 220V.
>
>I'm mostly a CW OP but I don't want to be known for a horrible SSB signal
>the few times I run this mess in AB1.
>
>So, what-cha think?   is 5% regulation acceptable on the screen of a 4-1000
>in AB1?

Nope.   A 5% change in Esc would produce c. 8% change in anode current.  
//  20mA of screen bleeder current would be plenty.  //  Short-circuit 
proof, RF proof regulated, solid-state screen supplies are easy to build. 
 A roadmap for an LM723-based pos. floating screen regulator ckt. is on 
my Web site.  The zero/full load reg. is so good that I can't measure the 
v drop on my Fluke 3.5 digit DMM.  
>
-  later, Bill


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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