# Digital Electronics MCQ with Answer

## Digital Electronics MCQ with Answer

Q1. Using the laws of Boolean algebra, the Boolean expression AB + (A+B)(B+C) can be simplified to

(a) A â€“ BC
(b) B + AC
(c) C + AB
(d) AB + AC

Q2. Which of the following gates is known as equality comparator?

(a) AND gate
(b) OR gate
(c) XNOR gate
(d) XOR gate

Q3. 10101 binary number corresponds to decimal number

(a) 31
(b) 21
(c) 11
(d) 3

Q4. The unique output for a NAND logic gate is a 0 :

(a) when all inputs are 0
(b) when all inputs are 1
(c) when any one input is 0
(d) when any one input is 1

Q5. Bubbled (inputs inverted) OR gate is equivalent to

(a) NOR gate
(b) NAND gate
(C) NOT gate
(d) XNOR gate

Q6. The minimum number of two input NAND gates required to realize the function of 3 input OR gate is

(a) 4
(b) 5
(C) 6
(d) 3

Q7. A bubbled (input inverted) OR gate is equivalent to

(a) NOR gate
(b) NAND gate
(c) NOT gate
(d) XNOR gate

Q8. The most suitable gate for comparing two bits is

(a) AND
(b) OR
(C) NAND
(d) X-OR

Q9. Which of the following gates cannot be used as an inverter ?

(a) NAND
(b) AND
(C) NOR
(d) X-NOR

Q10. How many NOR gates are required to obtain AND operation ?

(a) 2
(b) 3
(c) 4
(d) 1

Q11. Which of the following is a universal gate ?

(a) OR gate
(b) NOR gate
(c) AND gate
(d) NOT gate

Q12. Consider a Boolean Expression F = (B + BC)(B + Bâ€™C)(B + D) The minimum number of NAND gates required to implement this â€˜Fâ€™ will be

(a) 0
(b) 2
(c) 3
(d) 4

Q13. The number of comparators in a 4-bit flash A to D converter is

(a) 4
(b) 5
(c) 15
(d) 16

Q14. The minimum number of storage elements needed for the designing of a bi-stable multivibrator is:

(a) 0
(b) 1
(c) 2
(d) 3

Q15. The functional difference between SR flip-flop and JK flip-flop is that

(a) JK flip-flop has a feedback path
(b) JK flip-flop can accept both inputs as 1
(c) JK flip-flop does not require an external clock pulse
(d) JK flip-flop is faster than SR flip-flop

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