[sdiy] Inverting/noninverting attenuator circuit

[René Schmitz]

Hi all,

> Actiualy, it was the voltage doubler currently in Milton that Rene helped me
> with!

Oh, I wasn't aware of that. :-)

> GIzmo a bit different from this, uses 12 components, including a 2k trimmer
> and two op amps, (input buffering amp) as well prior to the pot  and output
> amp for tuning the null point to dead center.

Ah, yes. Buffering the input makes sense. Otherwise the null point might 
shift with changing output impedance of the driving circuit.
But then this wouldn't really be simpler than Tim's optional invertor.
The advantage would be a lower output impedance.

I have built some units based on the circuit I posted, I find these are 
highly useful. I have wired the inputs' switch contacts to +15V via a 
resistor, so this also can act as a tuneable bipolar voltage source.

Cheers,
  René

-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159