Read the Darlington confi guration concept described in Problem 2.9, and then turn to its pnp realization of Fig. P2.10. Assume RL 5 4 V and 2VS 5 212 V, and let the BJTs have, respectively, Is1 5 5...

Read the Darlington confi guration concept described in Problem 2.9, and then turn to its pnp realization of Fig. P2.10. Assume RL 5 4 V and 2VS 5 212 V, and let the BJTs have, respectively, Is1 5 5 fA and F1 5 100, Is2 5 100 pA and F2 5 40. Using vEB1 5 VT ln (iC1yIs1) for Q1, and vEB2 5 1.5VT ln (iC2yIs2) for Q2, fi nd the input current iI as well as the input voltage vI (accurate within 1 mV) needed to achieve: (a) vO 5 21 V, (b) vO 5 25 V. Hint: you can speed up your calculations using the rules of thumb.