Spehro Pefhany wrote:
>> > Sheesh.
>> >
>> > How can that work?
>>
>>The reverse B-E junction produces light, which illuminates the B-C
>>junction which acts like a photocell.
>>
>>I've tried it on TO-18 case transistors with the metal case cut open,
>>and you can see the light!
>
> Forgot to mention, you should probably toss the transistor after trying
> this, because zener-ing the B-E junction tends to degrade beta,
> more-or-less permanently.

Fifteen or so years ago I saw a schematic of a "solar" radio which was 
powered by a power transistor w/ the lid sawed off.

This is one thing I love about the PICList. They don't teach this stuff at 
school, and I didn't even think about the oscillator to -ve trick, or the 
opto trick. :)

Re: original question.. years ago Russell suggested splitting grounds using 
a Schottky. You use the "Schottky" ground as your "normal" tround, and the 
"normal" ground (now with a negative offset) for your opamp.

Vitaliy 

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