## Download Question Paper of "Digital Electronics 2 BSC IT(D)" , Question Paper of BSC IT(D) 2nd Semester, Subject Code : DCA-201, Paper ID A0305, Paper 1

• Wednesday, June 29, 2016
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Roll No. ...........................
Total No. of Questions : 13]

# DIGITAL ELECTRONICS

Time : 03 Hours

# Instruction to Candidates:

1)             Section - A is  Compulsory.
2)             Attempt any Nine questions from Section -  B.

# Section - A

Q1)
i.        Convert Hex BSC to binary.
ii.      Add binary numbers: 1101 + 1001 + 1111.
iii.      Convert decimal 100. 5 to binary.
iv.       What do you mean by minterm and maxterm?
v.      Write De-Morgan’s theorem.
vi.      Draw the symbol of a 4 input NAND gate and 3-input
vii.      What is the role of a half adder and half subtractor?
viii.      What do you mean by combinational circuits? Give exa
ix.      Where do we use MUX and DEMUX?
x.      Write the truth table of half adder and draw its circuit.
xi.      What are the various types of Flip Flop?
xii.      Where do we use Flip Flop and memories?
xiii.      How Register constitute a memory?
xiv.      Explain what do you mean by Main and Secondary me
xv.      Where do we use D-Flip Flop and clocked Flip Flops?

SECTION –B

2.       If X=1101.110 and y = 1001.101(both in binary) Find x+ y and x-y( by2’s
complement method).
3.       Convert hex Cf 8.7 to binary, octal and decimal system.

4.       simplify the following function by K-map:

a) F(A ,B,C) =∑(0,2,3,4,6)

B) XY +YZ+XY’Z

5)      simplify the following expression in (a) S-O-P and (b) P-O-S:

X’ z’+ y’ z +z y ’+x y

6)      write the truth table of a Full adder and then from it derive the circuit in terms of half adders.

7)      Draw the circuit of a 2 to 4 decoder and explain its function.

8)      Explain  how 3 to 8 decoder function can be obtained from a demultiplexer(1 to 8)

9)      draw the symbols and write the truth tables of the various logic gates you have studied

10)    draw the circuit of an S-R flip flop using NAND  gates only from it derive the circuit of a D-flip flop and explain its truth table.

11)    How can you realize the edge triggered J-K flip flop from an S-R flip flop? Write the truth table of J-K flip flop an explain how race – around problem can be solved in it.

12)    Explain the difference between the following memories:

a)     Volatile and Non – volatile
b)    Static and dynamic
c)     Sequential and random access.
d)    Magnetic and semiconductor.

13)    Discuss:

a)     Classification of memories.

b)    Basic memory structure