j.chitte wrote:
>
>
>
> This may also be a case of sinking current as well as sourcing
> current. IIRC the 197 in unipolar mode is biased at half full scale so
> voltages less than that will probably need the sampled source to sink
> current. Many applications supply current better than they sink it.
>
> As all correspondents suggested last time : buffer with an op-amp.
>
> (and check the amp's ability to sink).
>
Hehe... I am to hardware design as Bozo the Clown is to Shakespeare. :-)
I can wield a soldering iron usually without injury but that's about
it. Further, this is purely a hobby project so I don't have any
resources to draw on.
However, googling around I discovered an LM324, which looks like it will
work - 5 VDC supply, 4 on a chip so I only need 4 chips, and a simple
voltage divider to get the gain I need. Any hardware gurus confirm that
choice?
http://www.national.com/ds/LM/LM124.pdf
I'm thinking the non-inverting DC Gain circuit on page 9 will work.
No?
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