# Electronics and Communication Engineering - Digital Electronics

11.

Which of the following characteristic are necessary for a sequential circuit?

1. It must have 6 gates
2. It must have feedback
3. Its output should depend on past value
Which of the above statements are correct?

 A. 1, 2, 3 B. 1, 2 C. 2, 3 D. 1, 3

Explanation:

The number of gates may be any.

12.

10112 x 1012 = __________ 10

 A. 55 B. 45 C. 35 D. 25

Explanation:

1011 = 11 in decimal and 101 = 5 in decimal, 11 X 5 = 55.

13.

For the logic circuit of the given figure the simplified Boolean equation

 A. Y = (A + B) (C + D) (E + F) B. Y = A = B + C + D + E + F C. ABCDEF D. ABC + DEF

Explanation:

= (A + B) (C + D) (E + F).

14.

A combination circuit is one in which the output depends on

 A. input combination at that time B. input combination and previous output C. input combination and previous input D. present output and previous output

Explanation:

Combinational circuit does not have memory.

15.

718 = __________ .

 A. 1110002 B. 1110012 C. 1000012 D. 1100012