The output stage in the circuit shown in Figure P11.86 is a Darlington pair emitter-follower configuration. Assume \(\beta=120\) for all npn transistors and \(\beta=90\) for all pnp transistors. Let \(V_{A 7}=60 \mathrm{~V}\) for \(Q_{7}, V_{A 11}=120 \mathrm{~V}\) for \(Q_{11}\), and \(V_{A}=\infty\) for all other transistors. Determine the output resistance \(R_{o}\).

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V+ V+ Q6 Q7 29 V 1 = 0.2 mA V+ Qs R. Bias o Q11 'cx = 1 mA R = 5 k2 R=0.2 ks2 Figure P11.86