>
>Let us get the arithmetic right:
>Assuming we are talking, say, 3kV @ 1A peak power for the anode, then the
>screen load is trivial by comparison.
The screen is rated at 12w max.
>If building from iron collected from surplus sources, then making a 400V or
>whatever supply and tapping off for the screen, and then seriesing this with
>2.6kV to make up 3kV is no big deal.
400v at 1A is a big deal for the 12w screen.
>The resting anode current gives a bleed and helps stabilise standing volts.
>Sure, this is dearer than making a separate lighter screen supply and then
>electronically stabilising it if parts are bought new, but may be very cheap
>if parts are acquired surplus.
The zeners and power resistor to make a shunt-regulated screen supply for
a 4cx1000A would be c. $20.
>In effect the screen contribution becomes part of the anode supply, gratis.
>Just seems to me to be crude, simple, and likely highly effective.
>I would certainly sense the screen current and incorporate protective
>circuitry, regardless of where tha screen volts came from.
Mr. Rauch's math correctly showed that the screen dissipation rating
could not be exceed with a shunt regular powered from the anode supply.
>
cheers, Barry
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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