  # Digital Electronics MCQs with Answers For SPPU Exam 2020 Part 3

## Digital Electronics MCQs of Engineering Questions. This mcqs are useful in your university SPPU exams 2020, placements exams, GATE and others all exams.

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1. Boolean expressions for the output of Ex-NOR logic gate with inputs A and B
a. AB' + A'B
b. (AB. ' + AB
c. (A' + B. (A + B'.
d. (A' + B'. (A + B.

Ans: c

2. The minimum number of OR gates required to implement Y = A + AB' + AB'C is equal to
a. 2
b. 1
c. 4
d. 7

Ans: a

3. Given logical function of four variables F(A, B, C, D. = (A + BC. (B + CD. . The function as sum of product will be
a. AB + BC + ACD + BCD
b. AB + AB + AC'D + BCD
c. (AB + AB. ' + ACD + BC'D
d. AB' + A'B +A'CD + BCD

Ans: a

4. How many AND gates are required to realize Y = CD+EF+G?
a. 4
b. 5
c. 3
d. 2

Ans: d

5. The expression Y = AC + BD + EF is
a. POS
b. SOP
c. hybrid
d. none of above

Ans: b

6. The expression Y = ? m(0,1,3,4. is
a. POS
b. none of these
c. hybrid
d. SOP

Ans: d

7. In which function, is each term known as min term?
a. POS
b. SOP
c. hybrid
d. none of above

Ans: b

8. In the expression A + BC, the total number of min terms will be
a. 2
b. 3
c. 4
d. 5

Ans: a

9. The expression Y = pM(0,1,3,4. is
a. POS
b. SOP
c. hybrid
d. none of above

Ans: a

10. Which of the following is true?
a. SOP is a two level logic
b. POS is a two level logic
c. both SOP and POS are two level logic
d. Hybrid function is two level logic

Ans: c

11. In which function, is each term known as max term?
a. POS
b. SOP
c. hybrid
d. none of above

Ans: a

12. What are the two types of basic adder circuits?
c. asynchronous and synchronous
d. one's complement and two's complement

Ans: a

13. The result of binary addition 1+1 is
a. 1
b. 0
c. 10
d. 4

Ans: c

14. How many inputs does a Half-adder have?
a. 1
b. 2
c. 3
d. 4

Ans: b

15. How many outputs does a half adder have?
a. 1
b. 2
c. 3
d. 4

Ans: b

16. A full adder logic circuit will have
a. Two inputs and one output
b. Three inputs and three outputs
c. Two inputs and two outputs
d. Three inputs and two outputs

Ans: d

17. A combinational circuit that performs the addition of two input bits and a carry from the previous lower significant position is called
c. Full-subtractor
d. Half-subtractor

Ans: a

18. How many inputs will require for a 2:1 multiplexer?
a. 5
b. 8
c. 2
d. 1

Ans: c

19. The number of control lines for 2 to 1 multiplexer is

a. 2
b. 1
c. 3
d. 5

Ans: b

20. The number of control lines for a 8 – to – 1 multiplexer is
a. 2
b. 3
c. 4
d. 5

Ans: b

21. How many select lines will a 16 to 1 multiplexer will have?
a. 4
b. 3
c. 5
d. 1

Ans: a

22. How many outputs will require for a 1:4 demultiplexer?
a. 4
b. 8
c. 2
d. 1

Ans: a

23. The number of control lines i.e. select lines for 1 to 4 demultiplexer is
a. 2
b. 4
c. 3
d. 5

Ans: a

24. The number of control lines for 16 to 1 demultiplexer is
a. 2
b. 4
c. 3
d. 5

Ans: b

25. The number of control lines for 32 to 1 multiplexer is
a. 4
b. 5
c. 16
d. 6

Ans: b

26. One application of a digital multiplexer is to facilitate:
a. code conversion
b. parity checking
c. parallel-to-serial data conversion
d. data generation

Ans: c

27. What is applicable for demultiplexers ?
b. single input, multiple outputs
c. ac to dc
d. odd parity to even parity

Ans: b

28. Output of combinational circuit depends upon
a. Future input
b. Present input
c. Past and present
d. None of these

Ans: b

29. Multiplexer is
a. Combinational circuits
b. sequential circuits

c. either sequential or combinational circuits
d. none of above
Ans: a