[AMRadio] You Won't Believe This


Donald Chester k4kyv at hotmail.com
Sun Jan 2 18:11:15 EST 2005


>If you measure current from the filament transformer center tap to ground,
>you'll have not only cathode current, but plate current, as well.  Just 
>look
>over at the grid current meter, subtract that from the plate meter, and 
>there's
>your plate current, AND it's in a nearly ground potential position in the
>series circuit.


Return the grid leak resistor and/or PA bias supply to filament xfmr ct. 
instead of to ground, and your meter will read true plate current.  If it is 
a screen grid tube, return the negative lead of the screen supply to 
filament ct. as well.

Don k4kyv





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