Hi all!

Would anybody care to help a newbie out on OpAmp basics? I'm working
with some pressure sensors, one with static pressure for altitude
measurement and one differential for airspeed. I've searched the net for
basic opamp designs and found some useful pages.

I've set a span for the pressure ranges I'm interested in which is quite
less than the full dynamic range of the sensor. So I'd like to amplify
the signals to maximize ADC resolution over my range.

The amplification for the altitude sensor is inverting, which is good
since I get higher readings for higher altitudes with less pressure. I
worked from the description at
http://www.chipcenter.com/embapps/emba004.htm and now have a circuit
which produces the right values when simulated in Protel.

I do have trouble with the non-inverting one, though.

There's a good example at
http://www.tfs.net/~petek/rockets/altimeter/circuit.html, but I cannot
figure out how to go from the first circuit, with two opamps, to the
second with only one. I want to map a span of 0,2V - 0,439026V to the
ADC's 0-5V, non-inverting. And there might be issues with noise etc
since the interesting range is so narrow.
Of course, I could do it inverted and handle that in software, but
shouldn't this be a really basic thing??

I'd be happy to provide anyone with my calculations, circuits etc if
anyone's interested.

Regards,

Thomas

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.