AKTU Digital System Design · Important Questions 2026Source: ryzenstudy.com PYQs
BEC302 Digital System Design Important Questions 2026 (AKTU)
Repeat analysis + most-asked questions, unit-wise
What we did: built from all 4 AKTU Digital System Design papers (2021-22–2025-26): 96 questions grouped into 70 distinct questions, 17 of which were asked in more than one paper.
- of marks were repeat questions
- 38%
- of marks were repeat questions
- questions asked in 2+ papers
- 17
- questions asked in 2+ papers
- papers analysed (2021-22–2025-26)
- 4
- papers analysed (2021-22–2025-26)
- units, mapped to current syllabus
- 5
- units, mapped to current syllabus
How much of the paper repeats?
- Repeats are real: when we checked each newer BEC302 paper against the papers before it, on average 38% of its marks were questions already asked in an earlier paper.
- 2023-24 paper: 47% of marks were repeats (5 of 9 repeated questions were in our top list).
- 2025-26 paper: 30% of marks were repeats (3 of 8 repeated questions were in our top list).
- Topic weightage is a guide, not a guarantee: our Tier 1 + Tier 2 topics covered 68% of the next paper's marks — picking the same number of topics at random would have covered about 52%.
Across 10 subjects and 23 papers we tested, 43% of marks repeated earlier questions on average.
1.Unit-wise most-asked questions
Ranked by how many papers asked them, then by how recently. Click a paper to open it.
Unit 1:
19% of past marks| Question | Asked |
|---|---|
| Simplify the following expression using K-map (see original paper) | Asked 4× |
| Minimize the following using Quine-McCluskey method (see original paper) | Asked 2× |
| Convert the following: Hexadecimal equivalent of the decimal number 256; decimal equivalent of (123)9; 378.93 to octal; A3BH and 2F3H into binary (see original paper) | Asked 2× |
| Simplify the Boolean function. Also implement the minimized function using basic logic gates (see original paper) 7 marks2025-26 Q2(a) | Asked 1× |
Unit 2: Combinational circuits
21% of past marks| Question | Asked |
|---|---|
| What is a magnitude comparator? Design a two-bit comparator circuit using logic gates. | Asked 3× |
| Implement the following Boolean function using 4:1 MUX (see original paper) | Asked 2× |
| Design a full adder by constructing the truth table and simplify the output equations. | Asked 2× |
| Describe a circuit of 4-bit binary adder-subtractor with overflow detection. 7 marks2025-26 Q2(b) | Asked 1× |
Unit 3: Sequential logic design
21% of past marks| Question | Asked |
|---|---|
| With the help of a neat sketch, explain the operation of 4-bit universal shift register. | Asked 2× |
| Differentiate between Moore machine and Mealy machine. | Asked 2× |
| What is race around condition? | Asked 2× |
| Explain positive edge triggered D flip-flop with the help of circuit diagram and waveforms. | Asked 2× |
Unit 4:
18% of past marks| Question | Asked |
|---|---|
| Draw a circuit diagram of a CMOS inverter. Draw its transfer characteristics and explain its operation. | Asked 3× |
| What is fan-out in logic families? | Asked 3× |
| Design a 3-bit binary to Gray code converter using PLA. | Asked 2× |
| Draw and explain a NAND gate in totem pole TTL configuration. | Asked 2× |
Unit 5: Digital-to-Analog converters (DAC) · ADC Types
21% of past marks| Question | Asked |
|---|---|
| Explain switched capacitor and give its applications. | Asked 3× |
| Explain the principle of operation of an R-2R ladder DAC. | Asked 2× |
| Calculate the resolution. | Asked 1× |
| Assume the following values: ADC clock frequency = 1 MHz; VT = 0.1 mV; DAC has full-scale output = 10.23 V and a 10-bit input. Determine: (i) the digital equivalent obtained for V (ii) the conversion time (iii) the resolution of this converter (see original paper) 7 marks2025-26 Q2(e) | Asked 1× |
2.Topic weightage: which topics carry the marks
Blue = Tier 1 + Tier 2 (topics that carried ~80% of past marks). Grey = the rest. It shows where marks have gone, not a promise of what comes next.
Adders & subtractors · U2
9.2% (cum 9%)
TTL NAND & specifications · U4
8.7% (cum 18%)
ADC types · U5
6.8% (cum 25%)
K-map simplification · U1
6.4% (cum 31%)
Weighted resistor & R-2R DAC · U5
5.1% (cum 36%)
ADC specifications & principle · U5
5.1% (cum 41%)
Comparators · U2
5% (cum 46%)
S-R, JK & master-slave FF · U3
4.5% (cum 51%)
CMOS & interfacing · U4
4.1% (cum 55%)
Counters · U3
4% (cum 59%)
Boolean algebra & De Morgan · U1
3.9% (cum 63%)
PLD & FPGA · U4
3.6% (cum 66%)
Multiplexers & demultiplexers · U2
3.6% (cum 70%)
Mealy & Moore machines · U3
3.6% (cum 74%)
Switched capacitor circuits · U5
3.4% (cum 77%)
D, T & edge-triggered FF · U3
2.6% (cum 80%)
Number systems & conversions · U1
2.6% (cum 82%)
Shift registers · U3
2.6% (cum 85%)
Tabulation method · U1
2.4% (cum 87%)
Tristate TTL & ECL · U4
1.9% (cum 89%)
SOP, POS & canonical forms · U1
1.9% (cum 91%)
State diagrams & reduction · U3
1.6% (cum 93%)
Binary arithmetic & signed numbers · U1
1.4% (cum 94%)
Encoders & decoders · U2
1.3% (cum 95%)
Clocked sequential circuits · U3
1.3% (cum 97%)
Flip-flop conversion · U3
1.1% (cum 98%)
Combinational circuit design · U2
1.1% (cum 99%)
DAC specifications · U5
0.7% (cum 99%)
BCD adder, barrel shifter, ALU · U2
0.6% (cum 100%)
| Topic | Papers | Share |
|---|---|---|
| Adders & subtractors · Unit 2 · Tier 1 | 4/4 | 9.2% |
| TTL NAND & specifications · Unit 4 · Tier 1 | 4/4 | 8.7% |
| ADC types · Unit 5 · Tier 1 | 4/4 | 6.8% |
| K-map simplification · Unit 1 · Tier 1 | 4/4 | 6.4% |
| Weighted resistor & R-2R DAC · Unit 5 · Tier 1 | 3/4 | 5.1% |
| ADC specifications & principle · Unit 5 · Tier 1 | 1/4 | 5.1% |
| Comparators · Unit 2 · Tier 1 | 4/4 | 5% |
| S-R, JK & master-slave FF · Unit 3 · Tier 1 | 4/4 | 4.5% |
| CMOS & interfacing · Unit 4 · Tier 2 | 3/4 | 4.1% |
| Counters · Unit 3 · Tier 2 | 3/4 | 4% |
| Boolean algebra & De Morgan · Unit 1 · Tier 2 | 3/4 | 3.9% |
| PLD & FPGA · Unit 4 · Tier 2 | 3/4 | 3.6% |
| Multiplexers & demultiplexers · Unit 2 · Tier 2 | 3/4 | 3.6% |
| Mealy & Moore machines · Unit 3 · Tier 2 | 3/4 | 3.6% |
| Switched capacitor circuits · Unit 5 · Tier 2 | 3/4 | 3.4% |
| D, T & edge-triggered FF · Unit 3 · Tier 2 | 2/4 | 2.6% |
| Number systems & conversions · Unit 1 · Tier 2 | 3/4 | 2.6% |
| Shift registers · Unit 3 · Tier 3 | 2/4 | 2.6% |
| Tabulation method · Unit 1 · Tier 3 | 2/4 | 2.4% |
| Tristate TTL & ECL · Unit 4 · Tier 3 | 2/4 | 1.9% |
| SOP, POS & canonical forms · Unit 1 · Tier 3 | 2/4 | 1.9% |
| State diagrams & reduction · Unit 3 · Tier 3 | 2/4 | 1.6% |
| Binary arithmetic & signed numbers · Unit 1 · Tier 3 | 1/4 | 1.4% |
| Encoders & decoders · Unit 2 · Tier 3 | 1/4 | 1.3% |
| Clocked sequential circuits · Unit 3 · Tier 3 | 1/4 | 1.3% |
| Flip-flop conversion · Unit 3 · Tier 3 | 1/4 | 1.1% |
| Combinational circuit design · Unit 2 · Tier 3 | 1/4 | 1.1% |
| DAC specifications · Unit 5 · Tier 3 | 1/4 | 0.7% |
| BCD adder, barrel shifter, ALU · Unit 2 · Tier 3 | 1/4 | 0.6% |
3.Paper pattern (2025-26)
| Section | Questions | Rule |
|---|---|---|
| A | 6 × 2 marks | Attempt all |
| B | 5 × 7 marks | Attempt any 3 |
| C | 13 × 7 marks | Attempt any 1 |
4.In the syllabus, never asked yet
Low priority, but read them once — a new paper can always start here.
- Binary codes & conversion · U1
- Memory elements · U4
5.Study order
- 1Adders & subtractors (Unit 2, Tier 1)
- 2TTL NAND & specifications (Unit 4, Tier 1)
- 3ADC types (Unit 5, Tier 1)
- 4K-map simplification (Unit 1, Tier 1)
- 5Weighted resistor & R-2R DAC (Unit 5, Tier 1)
- 6ADC specifications & principle (Unit 5, Tier 1)
- 7Comparators (Unit 2, Tier 1)
- 8S-R, JK & master-slave FF (Unit 3, Tier 1)
- 9CMOS & interfacing (Unit 4, Tier 2)
- 10Counters (Unit 3, Tier 2)
- 11Boolean algebra & De Morgan (Unit 1, Tier 2)
- 12PLD & FPGA (Unit 4, Tier 2)
- 13Multiplexers & demultiplexers (Unit 2, Tier 2)
- 14Mealy & Moore machines (Unit 3, Tier 2)
- 15Switched capacitor circuits (Unit 5, Tier 2)
- 16D, T & edge-triggered FF (Unit 3, Tier 2)
- 17Number systems & conversions (Unit 1, Tier 2)
FAQ
Which units of BEC302 carry the most marks?
Unit 3 (Sequential logic design, 21% of past marks) and Unit 5 (Digital-to-Analog converters (DAC) · ADC Types, 21% of past marks).
Do AKTU Digital System Design questions repeat?
Yes. On average 38% of the marks in each newer BEC302 paper came from questions already asked in an earlier paper, and 17 questions have appeared in more than one paper.
How is this list made?
Every question from the 4 papers (2021-22–2025-26) was mapped to the current AKTU syllabus and grouped with the same question from other years. Questions are ranked by how many papers they appeared in, then by how recently.
Study this subject
Note: this is based on past AKTU papers, not a guarantee. Questions are mapped to the current syllabus; topics that are no longer in the syllabus are left out.