Part 1 of this article series explored general feedback-control-system analysis and synthesis as they apply to first-order transfer functions. The analysis technique was applied to both non-inverting and inverting op amp circuits, resulting in a frequency-domain transfer function for each configuration. Part 2 shows how to use these two transfer functions and manufacturer data-sheet specifications to analyze the DC gain error of a closed-loop op amp circuit. This analysis also takes into consideration the temperature dependency of the open-loop gain as well as its finite value.