He wouldn't find the op amp he's using in LT's library; he would've used another device in the simulation, and still been in the same predicament with the offset voltage.

Unless of course he managed to figure out how to add the SPICE model for a TL082 into LTSpice's libraries.

It's not hard to add models once you know how, but even if he had the TL082 model, he would have to modify it if he wanted to see the results of worst case parameters. The learning curve for LTspice is pretty steep. It's a useful tool, but it's not something you can just install, and become immediately proficient, as Jeepster sort of implied.

 

It's not hard to add models once you know how, but even if he had the TL082 model, he would have to modify it if he wanted to see the results of worst case parameters. The learning curve for LTspice is pretty steep. It's a useful tool, but it's not something you can just install, and become immediately proficient, as Jeepster sort of implied.

I don't think my goal is to learn a new simulation tool, just get my sensor values into my software world where I can more proficiently play. I ordered one of the Op Amps Sgt. Wookie recommended with an offset of 25 uv. Now that I know more (thanks to you all) I think it will work for what I'm doing. I could also have normalized the ADC but I felt I would lose too much precision since its a 10 bit part.

Given the incredible numbers of microprocessors available, it seems that all the custom HW I'll generally need for my projects is the ability to get sensor data in. LCDs, keypads, serial I/O, Ethernet, even wireless comms are all available without any significant HW development these days. A lot different then the "old" days, when electronics class consisted of experiments in biasing transistors and being in awe of how much easier they were then tubes to work with.

This is a pretty interesting site, though. Kind of glad the Op Amp problem made me find it.

 

Finally received and tried the LMV2011. What a difference ! My Op Amp output is now virtually linear across the whole input range. It was a bit sporting to solder wires to the SOIC package so I could plug it into my breadboard, though

Time to make a circuit board...

 

Glad things are looking up, Bob!

Even though the LMV2011 has far lower offset and far greater stability than the TL082, you should still write code to occasionally read/store the offset to minimize the errors that will otherwise accumulate over time.

 

Glad things are looking up, Bob!

Even though the LMV2011 has far lower offset and far greater stability than the TL082, you should still write code to occasionally read/store the offset to minimize the errors that will otherwise accumulate over time.

I'll be resetting/calibrating the circuit each time it's used. The use time will be a few hours at most.