Exam 2 with Solution for Electronics | ECE 2204, Exams of Basic Electronics

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ECE 2204 (Spring 2011) CoeCitig 75: ' Test #2 (oo. 69 = (57) Question #1 (50 points): Determine the values of V and Jin the circuit shown below. Both diodes should be modeled using the constant voltage drop approach with V,, = 0.7 V. Specify the operating states for D; and D2 and demonstrate that all other possibilities are not consistent with the constant voltage drop model. Ry, VPy=12V wien R,=6kQ Rz=12kQ Vy OQ R;=4kQ Rg=8kQ Question #2 (50 points): In the circuit shown below Vg = 5 V and R, = 1 MQ. Specify the junction area of Dz such that ¥, = 1 V (D; has a junction area of 1 mm’). Both diodes are made .. from. silicon. and_both. operate. at 300. K..Current flow in D, is dominated by. minority..carrier injection and diffusion (2 = 1). Current flow in Dy is dominated by carrier generation/recombination in the space charge region (n = 2). Show all intermediate steps to allow for the possibility of partial credit. jiode DI Dy Dy Ng= 1.2E+15 en bt Diode D2 Np= T4E+15 env} ; , + N,= 6.2B+18 cnr? %O ° Re $ My Np=4.8E+18 om? = 3.2E-04 sée _ b t= LISE-03 sec 7% 6.2E-08 sec D1 =D, 1 gnw, JOT — gy?) 2 ~ ye SF Je = = i an ¥, + z, 2] So EVD, L=, [D,z, February 17, 2011