12.9 (Note: Although rather long, this exercise is very instructive.) Consider the circuit of Fig. 12.16 with R1 = R2 = 5 kΩ, R3 = R4 = 0 Ω, and VCC = 15 V. Let the transistors be matched with IS = 3.3 × 10−14 A and β = 200. (a) For vI = 0 and RL = ∞, find the quiescent current in each of the four transistors and vO. (b) For RL = ∞, find iC1, iC2, iC3, iC4, and vO for vI = + 10 V and − 10 V. (c) Repeat (b) for RL = 100 Ω. (a) 2.87 mA; 0 V; (b) for vI = + 10 V: 0.88 mA, 4.87 mA, 1.95 mA, 1.95 mA, + 9.98 V; for vI = − 10 V: 4.87 mA, 0.88 mA, 1.95 mA, 1.95 mA, −9.98 V; (c) for vI = + 10 V: 0.38 mA, 4.87 mA, 100 mA, 0.02 mA, + 9.86 V; for vI = − 10 V: 4.87 mA, 0.38 mA, 0.02 mA, 100 mA, −9.86 V