# 2005 Madras University B C A Computer Application Digital logic fundamentals Question paper

** University Question Papers **

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**2005 Madras University B C A Computer Application Digital logic fundamentals Question paper

PART A - (10 x 3 = 30 marks)

Answer any TEN questions.

All questions carry equal marks.

1.Convert decimal 0.6875 to binary.

2. Use 2's complement to perform M-N with the given binary number

M = 1010100 N = 1000100

3.Write a note on "Error-Detection Codes".

4.Prove: x + x = x .

5.Construct the truth table for F = xy’ + x ' y .

6. Draw the logic F = x'y’z + x 'y z + xy’circuit for the expression

7. Give the logic diagram and graphic symbol for clocked RS flip-flop.

8.What are the functions of counter?

9.Describe the use of encoders.

10.What are Demultiplexers?

11.What is meant by accumulator?

12.Explain 'Minterms' with an example.

PART B - (5 x 6 = 30 marks)

Answer any FIVE questions.

All questions carry equal marks.

13.Write short notes on "Logic Gates".

14.Simplify the Boolean function using map method F =A'C+A'B+AB'C+BC

15.Explain the operations of status registers.

16. What is a decoder? Draw the logic diagrams of a BCD to decimal decoder and explain.

17. Explain with a logic diagram, the working of a full-adder.

18. Describe the operation of accumulator with neat diagram.

19. Describe about alphanumeric codes and error codes.

PART C - (4 x 10 = 40 marks)

Answer any FOUR questions.

All questions carry equal marks.

20.Perform the following in binary form.

(a) (128)10 - (64)10

(b) (l02) 10 + (120)10

(c) (31) 10 X (14) 10

(d) (25) 10 / (5) 10

21Prove the following equations:

(a) (X+Y)(X+Z)=X+YZ

(b) (A +B’+C)(A +B’+C’)(A +B +C) =A +B’C.

22. Explain the shift-right register and shift-left register with circuit diagram and truth tables.

23. Draw the block diagram of a ripple counter. Explain its operation. What is the advantage of a synchronous counter over ripple counter?

24. Explain the action of multiplexer and demultiplexer with suitable diagrams.

25.Describe the operation with function table of ALU