Digital System Design4_Logic Gates and Networks- 1

The outputof a logic gate is 1 when all the input are at logic 0 as shown below:

INPUT OUTPUT

A B C

0 0 1

0 1 0

1 0 0

1 1 0

INPUT OUTPUT

A B C

0 0 1

0 1 0

1 0 0

1 1 1

The gate is either

• A NAND OR AN EX-OR

• An OR OR AN EX-NOR

• An AND or an EX-OR

• A NOR or an

  EX-NOR

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

• Alphanumeric Code

• BCD

• Excess 3

• Gray

• 2 to 4 line

• 3 to 8 line

• 4 to 16 line

• 5 to 32 line

How many AND gates are required to realize Y=CD+EF+G ?

• 4

• 5

• 3

• 2

The NOR gates output will behigh if the two inputs are ---------

• 00

• 01

• 10

• 11

How many two -input AND and OR gates are required to realize Y=CD+EF+G ?

• 2,2

• 2,3

• 3,3

• 3,2

A universal logic gate is one which can be used to generate any logic function. Which of the following is universal logic gate ?

• OR

• AND

• XOR

• NAND

A full adder logic circuit will have -------------

• Two inputs and one output

• Three inputs and three outputs

• Two inputs and two outputs

• Three inputs and two outputs

How many two input AND gates and two input OR gates are required to realize Y=BD + CE + AB ?

• 3,2

• 4,2

• 1,1

• 2,3

Which of the following are known as universal gates ?

• NAND & NOR

• AND & OR

• XOR & OR

• X-NOR & XOR