[Boatanchors] OK Smart People- Back Bias

[Al Klase]

Won't work.  That circuit node has to be BELOW ground, which is 
impossible if the most negative end of the power supply is connected to 
ground.

Open up the 820-ohm resistor and clip in a 9-volt (or so)  battery with 
positive end grounded.

Al

On 7/31/2012 11:51 AM, David Stinson wrote:
> I have a BC-474 receiver that, as originally designed,
> uses a backbias resistor in the B- lead to provide audio
> PA and AVC bias.  R25 and C21 provide the bias.
> Here's the diagram:
>
> http://home.netcom.com/~arc5/bias/backbias.jpg
>
> I'd like to make a temporary "tacked-in" change so I can
> use a supply with B- grounded for a short time.
> Will 5-volt zeners connected this way work?
>
> http://home.netcom.com/~arc5/bias/zenerbias.jpg
>
> Thanks!
>
>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/