[Amps] Doorknob Caps Needed: Background

[Ron Youvan]

> Let me back up a tad on this. I am converting an SB-220 to 6 Meters.
> One of the questions I have is about the Plate Coupling Cap value. I see
> values of anywhere from 100 pF to 1,000 pF used. There must be some
> way to determine the appropriate value besides closing your eyes an
> picking one out of the box.

   The capacitor must have sufficient current carrying ability and DC
Voltage hold off ability and a low enough impedance (compared to the
impedance of the tube/s and the input of the output network) to prevent
a large drop (loss) across the capacitor.  Any more capacity (lower
impedance) hurts nothing and gets you nothing.  If the original works
use it.  If it explodes don't use it.  The original will have excessive
capacity at the higher frequency and should work just fine.
-- 
    Ron  KA4INM - No Micro$oft Products were used in sending this e-mail.
                                                 (or any since June 1997)