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[AMPS] Reverse-engineering design plate HV

To: <amps@contesting.com>
Subject: [AMPS] Reverse-engineering design plate HV
From: 2@vc.net (2)
Date: Thu, 15 Nov 2001 20:22:27 -0800
>
>//   The maximum AC potential across a blocking capacitor is typically
>less than a hundred volts at the lowest operating freq.  The maximum DC
>potential across one is the no-load anode supply voltage.  The critical
>rating is the RF ampere rating at the highest operating frequency.  I see
>no reason for the ARRL's statement.  QST no longer has a Technical
>Editor.
>
>In the 1999 ARRL Handbook (et al) on page 13.13, a formula is given
>as a "very rough rule of thumb" for figuring maximum RF current in a
>blocking capacitor @ 28 mhz. I "plugged in" 35pf anode C, 1 amp Ip,
>and 4 kv anode E. The result was 350 amps! (a bit high, me thinks!)
>Perhaps my ignorance of the "new math" caused an error????
>
//  It ain't the math.  I think this formula may have been from Dick 
Ehrhorn.  The current through the DC  blocking C is a function of 
anode-C, freq., and RMS anode V.  DC anode current has nothing to do with 
it.   Where Dick got this nonsensical formula is a mystery. 

cheers, Phil

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


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