CACS103 Digital Logic

Digital Logic TU Board 2024 question paper

8 questionsSit this paper (timed)

Tribhuvan University

Bachelor of Computer Application

Semester 1 · TU Board 2024

Course Title: Digital Logic (CACS103)

Full Marks: 60Pass Marks: 24Time: 3 hours

Candidates are required to answer the question in their own words as far as possible.

Group B

Attempt any SIX question.(6 × 5 = 30)

  1. 4.

    Differentiate between combinational and sequential logic circuits. Implement a full adder circuit using a decoder and two OR gates.

    5
  2. 5.

    Define priority encoder. Explain 8-to-3 priority encoder in detail.

    5
  3. 6.

    Explain the duality theorem with an example. Draw logic gates that implement the expression:

    5
  4. 7.

    How does a flip-flop differ from a latch? Explain clocked SR flip-flop with logic diagram, truth table, characteristic table, and excitation table.

    5
  5. 8.

    Write short notes on (any two): a) State reduction table  b) Multiplexe c) Synchronous and Asynchronous counter

    5

Group C

Attempt any TWO questions(2 × 10 = 20)

  1. 9.

    Differentiate between PAL and PLA. Design a combinational circuit with four inputs (BCD digit) and four outputs lines that generate the 2'Complements of the binary input pattern with circuit diagram, truth table, and block diagram.

    10
  2. 10.

    Explain shift register with parallel load. Design a synchronous Mod-10 counter to count in the sequence 0,2,4,5,6,8 using T flip-flops.

    10
  3. 11.

    Explain how race condition in JK flip-flop can be resolved. A sequential circuit with two D Flip-Flops (A, B), inputs , and output is defined by:

    10

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