[AMPS] Shunt regulated high voltage psu

[rich]

>
>Hi
>I need a 350 volts regulated power supply for a 4cx250 Linear Amp. I have
>650 volt unregulated available. The original circuit used a regulator with
>valves. I want to use solid state devices.

Sandeep:  
The 4cx250B and R have:  a low screen current requirement in linear 
service and a tendency to generate dangerous reverse screen-current.  
These two factors make the shunt zener screen regulator (powered through 
a resistance connected to the anode supply) a good engineering choice.   
Other benefits of a shunt regulator are:  1.  Accidental loss of anode V 
=s automatic loss of screen-V.  2.  By chosing an appropriate series 
resistance, the circuit is automatically screen current-limiting.  
-  A series of 5W. 20V - 30V zeners are a good choice for such a shunt 
regulator because they can be mounted on a perf-board, they are 
reasonably priced, and the screen V can be adjusted in 20 - 30 V steps.   
However, such zeners are 5W-rated only at 25ºC case temperature - which 
is quite unlikely at 5W in the real world.  Thus, a "5W" zener should be 
operated at no more than about 1.7 W -- except at the South Pole. 

I have two sockets and a bias supply transformer that I would like to 
find a home for,  If you pay the postage, I will send them to you.  

cheerio







-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, 
www.vcnet.com/measures.  
end


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