Hey
I've been trying to graspe common-mode voltage (op-ampS), but i ahven't found a decent explanation of it, probably because it is such a simple term it doesn't require much explaining. However i would like an explanation that helps when dealing with real world problems, for example noisey grounds, isolated grounds, op-amp input-offset specs, its relation to differential voltage that is amplified.
I would appreciate it if some had a few ideas on this.

If i tie the two inputs together and assume the input offset is ideal (0), will the output be zero
if the ground rail powering the op-amp is noisey?

Thanks

 

Check out the material in the AAC ebook on the topic of common-mode as it relates to opamps.

hgmjr