Most commercial op-amps are designed to be unity-gain stable [26]. That is, they are stable when used in a unity-gain configuration. To achieve higher bandwidth, some op-amps relax the requirement to be unity-gain stable. One such amplifier has a DC gain of 105 and a bandwidth of 10 kHz. The amplifier, G(s), is connected in the feedback circuit shown in Figure DP7.8(a). The amplifier is represented by the model shown in Figure DP7.8(b), where Ka = 105. Sketch the root locus of the system for K. Determine the minimum value of the DC gain of the closed-loop amplifier for stability. Select a DC gain and the resistors R1 and R2.
Figure DP7.8
(a) Op-amp circuit.
(b) Control system.

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GF) 3142K, × 1017 s 3142)s+10 R. VEs)