[AMRadio] Negative Loading circuits - good, bad, or ?

Brett gazdzinski Brett.gazdzinski at mci.com
Wed Jan 11 15:31:36 EST 2006

I use the one mentioned earlier, it used tubes and was in 
an old QST.
The variac is on the power supply that provides the 
voltage to the RF deck when the carrier is cut off.
This circuit uses 3 diodes, a load resistor, 
and the power supply.

Some circuits use a voltage dropping resistor instead 
of a power supply, but there is no easy way to adjust
the point at which you want the loading to start at.
You can also use a panel meter on the power supply 
(current) to show how hard you are into the loading...

> Brett,
> What circuit are you using?   The ones I referenced don't 
> call for variacs or 
> auxiliary power supplies.
> Dennis D. W7QHO
> Glendale, CA

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