Deemed University 2011 B.C.A Computer Application University: Lingayas University Term: III Title of the : Basics of Digital Electronics - Question Paper

Roll No. ..

 

Lingayas University

BCA 1^st Year (Term III)

Examination May 2011

Basics of Digital Electronics (EC - 1101)

 

[Time: 3 Hours] [Max. Marks: 100]

 

Before answering the question, candidate should ensure that they have been supplied the correct and complete question paper. No complaint in this regard, will be entertained after examination.

 

Note: Attempt five questions in all. All questions carry equal marks. Question no. 1 (Section A) is compulsory. Select two questions from Section B and two questions from Section C.

Section A

Q-1. Part A

Convert the following: [25=10]

(i) (ABC)₁₆=( )₂=( )₁₀

(ii) (10000111.1000)₂= ( )₁₀=( )₁₆

 

Q-1. Part B

(a) Perform the following operation using 2s complement method.

(i) 48-23

(ii) -48-23 [5]

(b) Why do you prefer 2s complements method in computer? [5]

Section B

Q-2. (a) Explain sequential and combinational circuit in detail. [10]

(b) What are counters? Explain the 3 bit counter in details. [10]

Q-3. (a) Explain J-K flip-flop and what is race around condition and how it is avoided? [10]

(b) Construct a 16*1 MUX using 2(8*1) MUX and 1(2*1) MUX. [10]

Q-4. Write short notes on:

(i) Ripple counter

(ii) Twisted Ring counter

(iii) D Flip-flop

(iv) DeMultiplexer [45=20]

 

Section C

 

Q-5. (a) Differentiate between RAM and ROM. [10]

(b) Explain Master-Slave flipflop in details. [10]

Q-6. (a) Design an adder/Subtractor circuit with one selection variable S and two inputs A and B. When s=0 the circuit perform A+B? When s=1 perform A-B by taking twos complement of B? [10]

(b) Minimize the 4 variable logic function using K-Map.

(i) F(A,B,C,D)=∑_m(0,1,2,3,5,7,8,9,11,14)

(ii) F(A,B,C,D)= Пm(2,7,8,9,10,12) [10]

Q-7. (a) Construct a 4*16 decoder with 3*8 decoder with enable input. [10]

(b) What are adder and subtractor? Explain Full adder and half adder. [10]

Q-8. (a) What are shift register and explain its application? [5]

(b) Construct an OR, AND, NOT using NAND. [5]

(c) Write short notes on any two:

(i) Binary Multiplexer

(ii) Ring counter

(iii) Universal gates [25=10]