# Download GTU B.Tech 2020 Summer 4th Sem 2140910 Digital Electronics Question Paper

Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 4th Sem 2140910 Digital Electronics Previous Question Paper

Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER? IV EXAMINATION ? SUMMER 2020
Subject Code: 2140910 Date:04/11/2020
Subject Name: Digital Electronics
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

MARKS
Q.1
(a) Convert (53.625)10 into an equivalent binary number.
03

(b) Compare 1's complement and 2's complement methods. Calculate 28 -19
04
using 2's complement method.

(c) State and prove DeMorgan's theorems with necessary figures and truth tables.
07

Q.2
(a) Prove that a positive-logic AND gate is a negative-logic OR gate.
03

(b) Explain the characteristics of digital logic families.
04

(c) Simplify the following Boolean expressions using K-maps:
07
(i) f = m(1,3,5,8,9,11,15),+,d(2,13)
(ii) F = M(1,2,3,8,9,10,11,14)?d(7,15)

OR

(c) Simplify the following Boolean expressions using Quine-McKluskey method:
07
f =
C
B
A
D
C
B
A
D
D
C
B
A
D
C
AB
C
AB D
Q.3
(a) Perform BCD addition of 91 and 81
03

(b) Compare combinational and sequential logic circuits
04

(c)
Write a short note on Gray code
07

OR

Q.3
(a) Explain even and odd parity codes.
03

(b) Design and analyze the working of a 1-bit comparator using logic gates
04

(c)
07

Q.4
(a) Explain the full adder circuit.
03

(b) Discuss the working of 3:8 decoder circuit.
04

(c)
Describe the working of 4:1 multiplexer. State the advantages of multiplexers.
07
1

OR
Q.4
(a) Differentiate between synchronous and asynchronous counters
03

(b) Explain the working of clocked RS flip-flop.
04

(c)
Write a short note on applications of shift registers.
07

Q.5
(a) Explain in brief universal shift register.
03

(b) Draw and explain the circuit of R-2R ladder.
04

(c) Write a short note on ring counter
07

OR

Q.5
(a) State the advantage of a ripple counter
03

(b) Define the following terms of DAC:
04
(i) Accuracy (ii) Resolution (iii) Linearity (iv) Settling time

(c)
Explain (i) Static RAM (ii) Dynamic RAM
07

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