(25 points) Consider the TTL circuit below. Assume all transistors are identical 04) (25 V Voc-5V VD(ON)=0.7V R4 kn R1200 Ra 2.5 kn Re1.6 kn VBE(FA) = 0.7V AZ D, VBE(SAT) = 0.8V DH Q Qu QA VCE(SAT) = 0.2V R4 kn Q D, VBC(SAT)=0.6V VBC(RA) = 0.7V BF 100 = P QAM 8 BR = 0.1 Da Da Rp 1 kn R₁1 k OF = 0.8 a. Determine the logic function. b. Sketch the voltage-transfer characteristics (VTC) for one input. c. Calculate the maximum fan-out.