CACS103 Digital Logic
Digital Logic: most repeated questions
Questions that have come up in more than one paper, matched by what they ask rather than exact wording. Most repeated first.
- 8×Asked in 2026, 2023, 2022, 2021, 2020, 2019What is a Decoder? Explain a 2:4 Decoder with its block diagram, truth table, and logic circuit.Answer coming5
See the wording in each paper
- What is a Decoder? Explain a 2:4 Decoder with its block diagram, truth table, and logic circuit.TU Board 2026
- What is a synchronous sequential circuit? Explain RS NAND latch with block diagram, logic diagram, truth table, and timing diagram.TU Board 2023
- Define Priority encoder. Design 4:2 priority encoder with its block diagram, truth table, circuit diagram and mathematical expression.TU Board 2022
- Define Decoder. Design BCD to Decimal decoder with its block diagram, truth table, circuit diagram and mathematical expression.TU Board 2021
- Define multiplexer. Explain 4:1 multiplexer with its block diagram, truth table and logic diagram. Mention how a 4:1 multiplexer works like lower order multiplexer.TU Board 2021
- Define Decoder. Explain binary to octal converter with block diagram, truth table and logic diagram.TU Board 2020
- Define Multiplexer. Explain 4:1 multiplexer with its block diagram, truth table and logic diagram.TU Board 2020
- Define decoder. Draw logic diagram and truth table of 3 to 8 line decoder.TU Board 2019
- 5×Asked in 2024, 2021, 2020, 2019, Model questionHow does a flip flop differ from a latch? Explain clocked SR flip flop with logic diagram, truth table, characteristic table, and excitation table.Answer coming5
See the wording in each paper
- How does a flip flop differ from a latch? Explain clocked SR flip flop with logic diagram, truth table, characteristic table, and excitation table.TU Board 2024
- Explain clocked JK flip flop with logic diagram, truth table, characteristic table and excitation table.TU Board 2021
- Explain JK and T Flip Flop with their Logic and Diagram, graphical symbol, characteristic table, characteristic equation and excitation table.TU Board 2020
- What is T Flip Flop? Explain clocked JK Flip Flop with its logic diagram and truth table.TU Board 2019
- Explain different types of flip flops (RS, JK) with truth table.Model question
- 5×Asked in 2026, 2022, 2021, 2019, Model questionWhat is 2's complement? Subtract (10110)₂ − (01011)₂ using 2's complement method.Answer coming5
See the wording in each paper
- What is 2's complement? Subtract (10110)₂ − (01011)₂ using 2's complement method.TU Board 2026
- Subtract: 11101.11110100.101 using both 1's and 2's complement.TU Board 2022
- Subtract: 453.35 321.17 using both 9's and 10's complement.TU Board 2021
- Subtract: 1010.110 101.101 using both 2's and 1's complement.TU Board 2019
- Subtract 23 from 18 using both 1's and 2's complement method.Model question
- 4×Asked in 2026, 2022, 2021Define Half Adder and Full Adder. Design a Full Adder circuit with its truth table, Boolean expressions, and logic diagram.Answer coming5
See the wording in each paper
- Define Half Adder and Full Adder. Design a Full Adder circuit with its truth table, Boolean expressions, and logic diagram.TU Board 2026
- Design full adder with truth table logical expression and logical circuit.TU Board 2026
- Define combinational circuit. Write a combinational circuit design procedure. Design a half adder with its truth table, logic diagram and Boolean expression.TU Board 2022
- Define combinational logic circuit. Design a full adder with its truth table, logic diagram and Boolean expression.TU Board 2021
- 4×Asked in 2022, 2021, 2020, 2019Simplify given Boolean function in both SOP and POS using k map where d represents don't care condition. F (A, B, C, D) = ∏(0, 1, 3, 7, 8, 12) and ∏ d(5, 10, 13, 14)Answer coming5
See the wording in each paper
- Simplify given Boolean function in both SOP and POS using k map where d represents don't care condition. F (A, B, C, D) = ∏(0, 1, 3, 7, 8, 12) and ∏ d(5, 10, 13, 14)TU Board 2022
- Simplify given Boolean function in both SOP and POS using k map where d represents don't care condition. F (A, B, C, D) = ∏ (2, 3, 4, 5, 7, 9, 10) and ∏ d (0, 6, 11)TU Board 2021
- Simplify the Boolean function F(w, x, y, z) = π(0,2,4,6,8,10,12,14) and don't care conditions d(w, x, y, z) = π(1,3,9,11) using K Map method for both SOP and POS form.TU Board 2020
- Simplify (using k map) the given Boolean function in both SOP and POS using the don't care condition if: f(A, B, C, D) = ℼ(0,1,3,7,8,12) ℼ d(5,10,13,14).TU Board 2019
- 3×Asked in 2022, 2021, 2019Differentiate between synchronous and ripple counter. Design mod 7 ripple counter with its state diagram, sequence table, logic diagram and timing diagram.Answer coming5
See the wording in each paper
- Differentiate between synchronous and ripple counter. Design mod 7 ripple counter with its state diagram, sequence table, logic diagram and timing diagram.TU Board 2022
- What is counter? Design a mod 7 synchronous counter with state table, state diagram, circuit diagram.TU Board 2021
- Design MOD 7 counter with state and timing diagram.TU Board 2019
- 2×Asked in 2022, 2019What is state diagram? A sequential circuit with two D flip flops A and B, one input x and one output z is specified by the following next state and output equations: A(t + 1) = A' + B, B(t + 1) = B' x, z = A + B' i) Draw the logic diagram of the circuit ii)…Answer coming10
See the wording in each paper
- What is state diagram? A sequential circuit with two D flip flops A and B, one input x and one output z is specified by the following next state and output equations: A(t + 1) = A' + B, B(t + 1) =…TU Board 2022
- A sequential circuit with two D flip flops, A and B, two inputs x and y, and one output z, is specified by the following next state and output equations. A(t + 1) = x'y + xA B(t + 1) = x/B + xA z =…TU Board 2019
- 2×Asked in 2023, 2020Explain the universal gates with their logic symbol, logic expression, and truth table. Realize an OR Gate using NAND Gate.Answer coming5
See the wording in each paper
- 2×Asked in 2022, 2021Why NAND and NOR gates are called universal gates? Realize NAND gate as universal gate.Answer coming5
See the wording in each paper
- 2×Asked in 2026, Model questionWhat is shift register? Explain different types of shift register.Answer coming5
See the wording in each paper
- What is shift register? Explain different types of shift register.TU Board 2026
- Explain bidirectional shift register.Model question