# Digital Logic Theory and Design BE Third Sem

(Established under section 3 of UGC Act, 1956)
Course & Branch: B.E – EIE
Semester: III Max. Marks: 80
Sub.Code: 6C0065 Time: 3 Hours
Date: 06-05-2008 Session: AN
PART – A (10 x 2 = 20)
1. Express the following decimal numbers in 2421 and 5421 code (i)
1993
2. State Demorgan’s theorem.
arrangement.
4. What is a tri-state gate?
5. Compare Encoder and decoder.
6. What is meant by a magnitude comparator?
7. Draw the logic diagram of a master – slave D-flip flop using NAND
gate.
8. What do you mean by critical and Non-critical races? How can they
be avoided?
9. Why are shift registers considered to be basic memory devices?
10. How can essential hazards be eliminated?
PART – B (5 x 12 = 60)
11. Using the K-map method, Simplify the following functions into
minimal sum of products
F(u,w,x,y,z)= (0.2,5,7,9,11,13,15,16,18,21,23,25,27,29,31)
(or)
12. Find the minimal sum of products for the Boolean expression,
F(a,b,c,d) = (1,2,3,7,8,9,10,11,14,15)

13. Discuss about the various parameters of TTL.
(or)
14. (a) Draw the basic BICMOS inverter, NAND and NOR gates and
explain its operation.
(b) Draw and explain the circuit diagram of a 3-input I2L NOR gate.
15. Explain briefly about the BCD – Seven Segment decoder.
(or)
16. Draw and explain the basic block diagram of PLA and what are the
steps used for implementing combinational circuit using PLA.
17. Design a synchronous counter with the following sequence counter
0000 0100 0100 0110 1000 1010 1100 1110 0000.
(or)
18. (a) Explain the working of serial in parallel out shift register with
logic diagram and waveforms.
(b) Explain about the various applications of flip-flops.
19. Obtain a static hazard free asynchronous circuit for the following
switching function.
F = (0,2,4,5,8,10,14)
(or)
20. Design an asynchronous circuit that will output only the first pulse
received whatever a control input is asserted from LOW to HIGH
state. Any future pulses will be ignored.
(ii) Timing Diagram