B.TechSemester 42025-26Digital ElectronicsBEE401

Digital Electronics (BEE401) - AKTU Question Paper 2025-26

B.Tech · Semester 4 · Free PDF Download

This is the official AKTU Digital Electronics Previous Year Question Paper for B.Tech Semester 4, academic session 2025-26. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.

Course:B.Tech

Semester:Semester 4

Session:2025-26

University:AKTU / UPTU

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Questions Asked in 2025-26

Digital Electronics (BEE401) — complete question paper · 70 marks · 3 Hours

Section AAttempt all questions in brief. 2x7 = 14

a
Convert the Octal number 245 into its decimal equivalent
b
Identify the logic gate that models a circuit with two switches connected in series
c
Explain the working of a multiplexer with an example
d
Illustrate the function of a flip-flop and give examples of any two types
e
For the design of a sequential circuit having nine states, Calculate the minimum number of memory elements required
f
Explain the basic function of an FPGA
g
Describe offset error in a D/A converter

Section BAttempt any three of the following: 7 x 3 = 21

a
Simplify the Boolean expression using K-map: Implement using NAND gates only
b
Construct a full subtractor circuit and explain its operation
c
Explain the working of JK flip-flop with truth table. Also draw its State Diagram
d
Determine the most suitable logic family for a system requirement using given parameters such as power, speed, and noise immunity
e
A 4-bit R-2R ladder type D/A converter having resistor values of R=10kΩ and 2R=20kΩ, uses VR of 10V. Calculate (a) the resolution of the D/A converter, and (b) I0 for a digital input of 1101

Section CAttempt any one part of the following: 7 x 1 = 7

a
Analyze the given Boolean expressions and derive their canonical forms
1
𝐴𝐵+𝐵𝐶̅𝐷+𝐴̅𝐷 2. (𝐴+𝐵ത)(𝐶̅ +𝐷ഥ)(𝐵ത +𝐶̅)
b
Examine the relationship between binary inputs and Gray code outputs in a 4-bit Binary to Gray Code converter
a
Implement the logic function given below using a 74151 eight input data selector/MUX
b
Apply the concept of cascading decoders to obtain outputs of a 5-to-32 decoder using two 4-to-16 decoders
a
Examine the state diagram and excitation table of a synchronous decade counter implemented using Toggle flip-flops
b
Analyze the behavior of a finite state machine used for sequence detection and justify its state transitions
a
Explain the construction and working of a TTL NAND gate with circuit diagram. Discuss its input-output characteristics
b
Describe the architecture and working of Programmable Logic Array (PLA)
a
Explain Flash Type ADC with relevant diagram. Discuss its applications
b
Interpret the operation of a 4-bit weighted resistor type D/A converter

Question text is extracted from the official AKTU question paper PDF above. Hindi translations are omitted — every question is printed in English in the original paper. Last verified: 2026-08-23.