I'm going to be doing some tests with a load cell that outputs 800 uV/V. I'm going to excite it with 5V, so my max. output will only be 4 mV, and the load I'm interested in will only produce 600 uV. I'd like to monitor this with a 5V Arduino that will have a 10 bit AD. I figure I should to try to scale my 600 uV signal to 2.5V to put it in the middle of the AD's range. That calls for a gain of 4166. If I use an op amp (like the MCP6004, because I happen to have some of those sitting around; datasheet here, http://ww1.microchip.com/downloads/en/DeviceDoc/21733j.pdf), the gain is R1/R2 + 1. Can I then just use, say, 42K and 10 ohm resistors (or others providing the same ratio)? I've never used op amps before, and I'm reading/watching various tutorials here and elsewhere, but that's what it's starting to look like. I realize there will be issues like common mode gain, drift, etc., but are there any major, "You've totally misunderstood and you can't do that, you pathetic wanker" issues? Is it better to use two op amps in series, each with a gain of about 64 (square root of 4166)? Any tips at all would be appreciated.