Digital Electronics

Daffodil International University Department of Electrical and Electronic Engineering Faculty of Engineering Midterm Examination, Fall-2026 Course Code: 0714-323 Course Title: Digital Electronics Section: A, B, C, D Level-Term: L2-T3 Teacher's Initial: DAS, BS Full Marks: 25 Exam Date: November 01, 2026 Time: 1.5 Hours [Notes: Answer all the questions. The number on the rightmost side of the question indicates the marks] Q1. (a) Represent your student ID in 84-2-1 code. Perform the following subtraction operation using both r's and (r-1)'s complement: 11111)_2 - 1111)_2 [CO1 (C3)] [5+3+4] (b) Simplify the following Boolean function to a minimum number of literals using the laws of Boolean algebra. F(a, b, c, d) = (b'c' + d)' + d + bc + ad (c) Using K-map find the simplest form in SOP and POS for the following Boolean function: F(w, x, y, z) = ∑(1, 3, 7, 11, 15) with the don't care conditions given by d(w, x, y, z) = ∑(0, 2, 5) Q2. (a) Implement the following Boolean function using NAND gates only. [CO1 (C3)] [3+3] F(x, y, z) = x + y'z (b) Implement the full subtractor circuit using half subtractor circuits and external gates. [CO3 (C3)] Q3. (a) Define the following performance characteristics of digital logic families: Propagation Delay, Noise Margin and Figure of Merit. [CO2 (C2)] [3+4] (b) Draw and properly labeled circuit diagrams of the CMOS AND and CMOS OR gates.