PDRUNEN@AOL.COM wrote:
>
> Hi Group,
>
> I have an op-amp circuit operating in the non-inverting mode with 36x
> amplification.  The Rf is 100k and the Rv is appr 3K.  I need to circuit to
> back down the gain at cold temperatures.
>
> At the low end of 0 deg, the gain would be 18 and at the high end 120 deg,
> the gain would be 36x, as a function of temperature.  So we would start with
> Rv near 3k and end with Rv near 6k.
>
> Is there a better method than using a thermistor for Rv?  Could a transistor
> or diode, FET or other be used to control the gain?  I could use a digital
> POT but that may be more expensive than desired.
>
> Thanks,
>
> Paul

have you worked out the conversions yet to get a readout in F or C..
PITA.. depending on your temperature range you might check into Dallas's
digital themp sensors.. of course they are like $6-8 in single quantity
but need no extra parts.

                Damon Hopkins