The op-amp inverting amplifier circuit is an example of a negative feedback circuit. The practical op amp is modeled with a large DC gain and a dominant low-frequency pole, and a block diagram is developed and solved. Graphical construction of the loop gain and the closed-loop transfer function leads to the actual transfer function with a practical nonideal op amp. Loop bandwidth, stability and phase margin, closed-loop output impedance, and gain-bandwidth product are analyzed.