Here is a application guide from Texas Instruments is an overview of operational amplifier-related circuits, theory, and formulas. Inverting amplifiers, buffers, analog adders, filters, and many more are covered.
The general utility of the operational amplifier is derived from the fact that it is intended for use in a feedback loop whose feedback properties determine the feed-forward characteristics of the amplifier and loop combination. To suit it for this usage, the ideal operational amplifier would have infinite input impedance, zero output impedance, infinite gain and an openloop 3 dB point at infinite frequency rolling off at 6 dB per
octave. Unfortunately, the unit cost–in quantity–would also be