Question

Among the following which one gives output $1$ in a two input AND gate.
A) $A = 0,B = 0$
B) $A = 1,B = 1$
C) $A = 1,B = 0$
D) $A = 0,B = 1$

Answer 1

At first, the two-input AND gate should be considered. Thereafter the truth table of the AND gate is used. Here in the problem, the values of two inputs are given to find the required output. There is an existing value of the output of an AND gate regarding the values of its input-pair. In other words, it can be said that the output differs in terms of the combination of inputs.

Complete answer:
Let us consider an AND gate of two inputs $A$ and $B$ and let $Y$ be the output.
Then the AND gate symbol will be as shown below

The truth table of this AND gate is:

Input-${{A}}$	Input-${{B}}$	Output-${{Y}}$
${{0}}$	${{0}}$	${{0}}$
${{0}}$	${{1}}$	${{0}}$
${{1}}$	${{0}}$	${{0}}$
${{1}}$	${{1}}$	${{1}}$

Using the above truth table let us consider the given options to find the value of the output is $1$.
Option (A): $A = 0,B = 0$
For $A = 0,B = 0$ we get the output $Y = 0$. Hence, this is not the right answer.
Option (B): $A = 1,B = 1$
For $A = 1,B = 1$ we get the output $Y = 1$. Hence, this is the right answer.
Option (C): $A = 1,B = 0$
For $A = 1,B = 0$ we get the output $Y = 0$. Hence, this is not the right answer.
Option $(D){\text{ }}A = 0,B = 1$
For $A = 0,B = 1$ we get the output $Y = 0$. Hence, this is not the right answer.
Therefore, option (B) is the only correct option.

Note:
An AND gate has two or more input signals and one output signal regarding the inputs.
In the AND gate for two or more high inputs we get the high input and for any one of the low inputs, we get low output.
The high input means when the value is $1$ and the low input means the value is $0$.
The boolean algebra regarding the AND gate of two input is $Y = A.B$ and of three inputs is $Y = A.B.C$