The infinite gain approximation is very useful but a more complete description is required if we are to understand the limitations of the op-amp. Real op-amps have a large but finite input impedance, small but non-zero output impedance and large but finite open-loop gain. They also have voltage and current asymmetries at the inputs. We will analyze some circuits using an finite open-loop gain and consider output impedance, input impedance, and voltage and current offsets.

Tue Jul 13 16:55:15 EDT 1999