Digital Electronics Unit 2 – Combinational Logic: AKTU previous year questions
51 AKTU questions from Unit 2 (Combinational Logic) asked in 2022–2026, tagged by marks, year and topic. In short: about 31 marks of every paper come from this unit; the most asked topic is Adders and Subtractors (22 times); 43 questions came back in a later year. The latest ones are listed below; on the page you can filter them by 2-mark or long questions, topic and repeats.
Unit 2 previous year questions
- State the function of an encoder. (2 marks, 2026, Encoders and Decoders)
- What is a multiplexer? Write any two applications. (2 marks, 2026, Multiplexer and Demultiplexer)
- Design a full subtractor circuit using two half subtractors and basic gates. (7 marks, 2026, Adders and Subtractors)
- Explain the operation of a 4-bit priority encoder with truth table and logic diagram. (7 marks, 2026, Encoders and Decoders)
- Design a Full Adder using two Half Adders and basic gates. (7 marks, 2026, Adders and Subtractors)
- Implement a 4:1 multiplexer using 2:1 multiplexer. (2 marks, 2025, Multiplexer and Demultiplexer)
- What is a magnitude comparator used for? (2 marks, 2025, Magnitude Comparator)
- Discuss multiplexed display systems. How are they used in practical applications? (7 marks, 2025, Multiplexed Display)
- Explain the working of a BCD adder. How does it differ from a binary adder? (7 marks, 2025, Adders and Subtractors)
- Explain the look ahead carry generator with neat diagram. (7 marks, 2025, Adders and Subtractors)
- Describe half subtractor circuits with truth tables and circuit diagrams. (7 marks, 2025, Adders and Subtractors)
- Implement the following function. F (A, B, C, D) = ∑m (0, 1, 3, 4, 7, 8, 9, 11, 14, 15) using 1. 8:1 MUX 2. 4:1 MUX (7 marks, 2025, Multiplexer and Demultiplexer)
Most asked Unit 2 topics
- Adders and Subtractors – asked 22 times
- Multiplexer and Demultiplexer – asked 15 times
- Magnitude Comparator – asked 7 times
Unit 2 question pattern
- 2-mark questions: 17 asked in 2022–2026
- 7-mark questions: 11 asked in 2022–2026
- 10-mark questions: 23 asked in 2022–2026
- About 31 marks from Unit 2 in every paper
- 43 questions were asked again in a later year
Unit 2 questions year by year
- 2026: 5 Unit 2 questions asked (25 marks across that year's papers)
- 2025: 7 Unit 2 questions asked (39 marks across that year's papers)
- 2024: 5 Unit 2 questions asked (25 marks across that year's papers)
- 2023: 22 Unit 2 questions asked (164 marks across that year's papers)
- 2022: 12 Unit 2 questions asked (88 marks across that year's papers)