The non-inverting op amp configuration is most common for low noise applications so we’ll make that the focus. Modeling the input source as a voltage source with a series resistance (figure 1), we ...

The op amp's inputs are made up of an inverting input (V in-) and a non-inverting input (V in+). In the ideal case, the op amp amplifies the difference in voltage between the two inputs.

The end result is that, with R 4 , the op amp's effective gain-bandwidth-product (GBWP) is decreased. We can eliminate this GBWP degradation by applying the feedback signal to the non-inverting ...

2. In an inverting and single non-inverting input op-amp summer, R1-R3 interact to some extent (Equation 2). Equation 2 is still manageable: R1-R3 are interactive, but not terrible to deal with. 3.

An op amp with +/-15V on the rails can’t produce 50V to wrestle the input to a particular value. But for common sense applications, those assumptions will take you a long way.