West Bengal Institute of Technology (WBIT) 2008 B.C.A Computer Application 101 Digital Electronics ( ) - Question Paper
CS/BCA/8EM-1/BCA-101/08/(09)
ENGINEERING & MANAGEMENT EXAMINATIONS, DECEMBER - 2008
DIGITAL ELECTRONICS SEMESTER -1
Tim? : 3 Hours ] [ Full Marks : 70
GROUP-A ( Multiple Choice Type Questions }
1. Choose the correct alternatives for any ten of the following : 10 x 1 = 10
i) (1100-1011)2-(?)10
a) 10-6785 b) 11-6578
c
c) 12-6875 d) 13-6785.
ii) 2's complement of 10101100 is ' a) 11001010 b) 01010011
c) 01010100 . d) 01011001.
iii) (247-36)8-(?)l6 . a) A7-78 b) 1A7-36
c) B7-87 d) 1B7-36.
iv) MBR, in reference to memory management is a) Memory Broad Register b) Memory Buffer Relay
c) Memory Buffer Register d) None of fiiese.
v) Output of NAND gate is 1, if and only if
% .
a) all inputs are 1 b) any input is 1
c) all inputs are 0 d) any input is 0.
11006 (S/lg)
CS/BCA/SEM-l/BCA-101 /08/(09)
vi) A + A-?
b)
a) 1
c) A , d) A.
vii) If the no. of states of a counter is 8, then the no. of flip-flops is
a) 8
b) 3
d) 6.
b) A + B
d) 1.
c) 4
viii) (A.B +A.B +A.B) 16 equal to
a) A + B
c) A + B
ix) Karnaugh Map is used to
a) simplify Boolean function
b) design Boolean function
c) evaluate Boolean function . d) none of these.
x) A multiplexer has
b) multiple output d) single output.
a) single input
c) no output
xi) Output of R-S ( NAND ) flip-flop, for R = 1 & S = 1 is 'a) set b) reset
c) race d) no change.
xii) Subtracting 1111 from 11000 will result to
a) 1000 b) 1100
GROUP-B (Short Answer Type Questions )
Answer arty three of the following. 3x5= 15
2. Apply K-map to obtain the minimal form for the function :
F ( A, B, C, D ) = Z ( 0, 4, 5, 7, 8, 9, 13, 15 )
d( A, B, C, D ) = Z ( 1, 2, 6, 10 )
3. Draw a half-adder circuit and describe its operations.
4. Design a 4-bit up-down counter.
5. Prove the following logical equation using Boolean algebra :.
(A+BC). (B+AC) = BC + AC
6. i) Subtract (7489)1(3-(2485)10 using 10s complement method.
ii) What is a Multiplexer ? Why is it called "Data selector" ?
GROUP-C ( Long Answer Type Questions )
Answer any three of the following questions. 3 x 15 = 45
7. a) Represent the decimal number "27" in
i) BCD code
ii) Octal code
iii) Gray code. . . - .
b) Draw the block diagram of a digital multiplexer and explain its function.
c) Give the functional truth table of a 4 : 1 multiplexer and realize it using basic gates AND, OR and NOT.
d) Implement the expression using a multiplexer :
CS/BCA/SEM-1 /BCA-101 /OB/1O0] 6
8. a) What do you mean by a sequential circuit ?
b) What are synchronous & asynchronous sequential circuits ?
c) Explain the functionality of D-fUp-flop. Give the truth table. State diagram.
d) What do you mean by Edge-triggering & Level-triggering in flip-flops ?
2 + 3 + 5 + 5
9. a) What is a flip-flop ?
b) What are the uses of flip-flops ?
c) Give the circuit diagram of a J-K flip-flop.
|
Inputs |
Outputs | |||
|
X |
y |
z |
FI |
F2 |
|
0 |
0 |
0 |
0 |
0 |
|
0 |
0 |
1 |
1 |
0 |
|
0 |
1 |
0 |
1 . |
0 |
|
0 |
1 |
1 |
0 |
i 1 |
|
1 |
0 |
0 |
1 |
0 |
|
1 |
0 |
1 |
0 |
1 |
|
1 |
' 1 |
0 |
0 |
1 |
|
1 |
1 |
1 |
1 |
1 |
I) Obtain the simplified functions in sum of products,
ii) Obtain the simplified functions in product of sums,
b) Design a BCD to Exess-3 Code converter.
11. a) Explain different types of RAM and ROM.
b) Write short notes on any tujo of the following : f
i) Parity checker
ii) Ring counter t
iii) Magnitude comparator.
END
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Attachment: |
| Earning: Approval pending. |
