An ac equivalent circuit of a Darlington pair configuration is shown in Figure P6.79. The transistor parameters are \(\beta_{1}=120, \beta_{2}=80, V_{A 1}=80 \mathrm{~V}\), and \(V_{A 2}=50 \mathrm{~V}\). Determine the output resistance \(R_{o}\) for

(a) \(I_{C 2}=I_{\text {Bias }}=1 \mathrm{~mA}\);

(b) \(I_{C 2}=1 \mathrm{~mA}, I_{\text {Bias }}=0.2 \mathrm{~mA}\); and

(c) \(I_{C 2}=2 \mathrm{~mA}\), \(I_{\text {Bias }}=0\).

Transcribed Image Text:

AC ground Figure P6.79 Bias 22 Ro