Model Question Paper

BSCO4- SWITCHING CIRCUITS AND LOGIC DESIGN

Duration : 3 hrs Maximum Marks: 75

Instruction:

1. Question paper is divided into Group A, Group B, and Group C
2. Each Group is of 25 marks
3. Figure to the right in bracket indicate marks.
4. Good Handwriting is expected.

 

Group A (25 Marks)

Answer any three questions (Question 1 is compulsory)

1.                  Convert the following expression into sum of products and products of sums :

(A B + C) (B + C D) (5)

2.                  Simplify the following Boolean function using three variable maps

(a)    F(x,y,z) = (2, 0, 3, 4, 6)

(b)    A B + B C + B C (10)

3. Design a code converter that converts a decimal digit from the 8-3-2-1 code to BCD. (10)

4. Design a 4-bit binary synchronous counter with D flip-flop. (10)

5. Design an even parity generator for 5-bit data. Realize the above even above even parity

generator using suitable multiplexer IC (10)

 

Group B (25 Marks)

Answer any three questions (Question 6 is compulsory)

6.                  Obtain Exclusive-OR gate and Exclusive-NOR gate, using OR gate and NOT gate. (5)

7.                  Consider following Boolean expression:

Y = E₃ E₁ + E₁ E₀ + E₂ E₁ E₀

i) Show K map for this function

ii) Reduce the expression using Boolean theorem.

iii) Reduce it by using K map. (10)

8.                  Explain Master-Slave flip-flop with truth table, logic diagram and uses. (10)

9.                  What is programmable logic array. How PLA is implemented in combinational -circuits, explain with a suitable example ? (10)

10.              What are Metal-oxide semiconductor (MOS) ? Explain characteristics of CMOS circuits. (10)

 

Group C (25 Marks)

All questions are compulsory.

 

Q. 11. Fill in the blanks (Each question carries 2 marks, Total = 10 marks)

 

(i) The flip-flops are widely used in digital systems as _____________.

(ii) The Binary equivalent of decimal 15 is ._____________.

(iii) The output is high only when all inputs are high, it is ___________ gate.

(iv) If two input of a NAND gate are connected to each other , the resultant output will be _________ gate.

(v) The minimum number of flip-flops needed to construct a BCD decoder counter is _____________.

 

 

 

 

 

Q. 12. Multiple choice questions (Each question carries 2 marks, Total = 10 marks) Select the correct answer.

 

(i) The Excess-3 code for (37)₁₀ is ________________.

(a)                0110 1010

(b)               1111 1010

(c)                1010 1101

(d)               none of these

(i)                 A flip-flop can store

(a)                4 bits

(b)               1bit

(c)                2 bits

(d)               8 bits

(iii) The Truth Table of a logic circuit lists :-

(a) All possible inputs

(b) All possible outputs

(c) Both of them

(d) None of them

 

(iv) A decoder has

(a)                n input and 2ⁿ output

(b)               2ⁿ input and n outputs

(c)                both (a) and (b)

(d)               none of these

(v) In general, a logic gate whose all output entries are logic 0 except one entry that is 1 is

(a)    either AND or NOR

(b)   either NAND or NOR

(c)    either EX-OR or EX-NOR

(d)   either AND or OR

 

Q. 13. Indicate whether following statements are True or False (Each question carries 1 marks, Total = 5 marks)

 

(i) NAND and NOR gates are called universal gates.

(ii) Modern computers communicate and operate with binary numbers.

(iii) ROM and RAM are combinational and sequential logic respectively.

(iv) Output section contains OR gates to produce the desired function

(v)                An encoder performs just a reverse decoder function.

 

 

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