Digital Electronics 2

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Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject:  Digital Electronics 2

Part 2: List for questions and answers of Digital Electronics


Q1. The NAND gate output will be low if the two inputs are

a) 00

b) 01

c) 10

d) 11


Q2. The number of control lines for a 8 – to – 1 multiplexer is

a) 2

b) 3

c) 10

d) 5


Q3. The Gray code for decimal number 6 is equivalent to

a) 1100

b) 1001

c) 0101

d) 0101


Q4. The gates required to build a half adder are

a) The gates required to build a half adder are

b) EX-OR gate and OR gate

c) EX-OR gate and OR gate

d) Four NAND gates


Q5. The code where all successive numbers differ from their preceding number by single bit


a) Binary code

b) BCD

c) Excess – 3

d) Excess – 3


Q6. Karnaugh map is used for the purpose of

a) Reducing the electronic circuits used

b) To map the given Boolean logic function

c) To minimize the terms in a Boolean expression

d) To maximize the terms of a given a Boolean expression 


Q7. 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


Q8. In _____ circuit does not need memory.

a) Combinational

b) Sequential

c) parallel

d) None of these


Q9. Which of the following are examples of combinational circuit?

a) Adder

b) Comparator

c) Both (A) and (B)

d) None of these


Q10. If Y=AC+BC is given expression then A,B and C are called as_____

a) Minterm

b) Maxterms

c) Literal

d) All of above


Q11. Quad eliminates _____variables

a) Two

b) Four

c) Three

d) Five


Q12. _____ eliminates three variables

a) Quad

b) Octet

c) Pair

d) None of these


Q13. Don’t care condition (X) may be assumed to be _____.

a) 0

b) 1

c) 0 or 1

d) None of these 


Q14. IC 74LS153 is a ______

a) 4:1 mux

b) 8:1 mux

c) 8:1 mux

d) Dual 4:1 mux


Q15. ……… Are used for converting one type of number system in to the other form

a) Decoder

b) logic gate

c) half adder

d) Full adder


Q16. A 4:1 Demux has _________ input and __________ outputs

a) 1,4

b) 4,1

c) 2,4

d) 4,2


Q17. A circuit that can convert one of ten numerical keys pressed on a keyboard to BCD is a


a) Priority encoder

b) Decoder

c) Multiplexer

d) Demultiplexer


Q18. How many 3-line-to-8-line decoders are required for a 1-of-32 decoder?

a) 1

b) 2

c) 4

d) 8


Q19. How many data select lines are required for selecting eight inputs?

a) 1

b) 2

c) 3

d) 4 


Q20. How many 1-of-16 decoders are required for decoding a 7-bit binary number?

a) 5

b) 6

c) 7

d) 8 


Part 2: List for questions and answers of Digital Electronics


Q1. Answer: d


Q2. Answer: b


Q3. Answer: c


Q4. Answer: c


Q5. Answer: d


Q6. Answer: c


Q7. Answer: d


Q8. Answer: a


Q9. Answer: c


Q10. Answer: c


Q11. Answer: a


Q12. Answer: b


Q13. Answer: c


Q14. Answer: d


Q15. Answer: a


Q16. Answer: b


Q17. Answer: a


Q18. Answer: c


Q19. Answer: c


Q20. Answer: d