Classical

Digital Logic - Combinational Circuits

11:   Which of the following gates would output 1 when one input is 1 and other input is 0 ?
A. OR gate
B. AND gate
C. NAND gate
D. both (a) and (c)
 
 

Option: D

Explanation :


12:   Which of the following statements is wrong ?
A. Propagation delay is the time required for a gate to change its state
B. Noise immunity is the amount of noise which can be applied to the input of a gate without causing the gate to change state
C. Fan-in of a gate is always equal to fan-out of the same gate
D. Operating speed is the maximum frequency at which digital data can be applied to a gate
 
 

Option: C

Explanation :


13:  

Which of the following expressions is not equivalent to X ' ?

A.

X NAND X

B.

X NOR X

C.

X NAND 1

D.

X NOR 1

 
 

Option: D

Explanation :

Answer is C as 
if X= 0  then X NAND 1 = 1 = X '
if X=1 then X NAND 1= 0=  X'

In Option (d)
if  X= 0 then X NOR 0 = 1 = X'
if X=1 then X NOR 1= 0 <> X' 


14:   Which of the following gates are added to the inputs of the OR gate to convert it to the NAND gate ?
A. NOT
B. AND
C. OR
D. XOR
 
 

Option: A

Explanation :


15:   The EXCLUSIVE NOR gate is equivalent to which gate followed by an inverter ?
A. OR
B. AND
C. NAND
D. XOR
 
 

Option: D

Explanation :




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