In the circuit, the logical value of $A=1$ or $B=1$ when potential at $A$ or $B$ is $5 \mathrm{~V}$ and the logical value of $A=0$ or $B=0$ when potential at $A$ or $B$ is $0 \mathrm{~V}$.
The truth table of the given circuit will be :
$$\matrix{
A & B & Y \cr
0 & 0 & 0 \cr
1 & 0 & 0 \cr
0 & 1 & 0 \cr
1 & 1 & 1 \cr
} $$
$$\matrix{
A & B & Y \cr
0 & 0 & 0 \cr
1 & 0 & 1 \cr
0 & 1 & 1 \cr
1 & 1 & 1 \cr
} $$
$$\matrix{
A & B & Y \cr
0 & 0 & 0 \cr
1 & 0 & 0 \cr
0 & 1 & 0 \cr
1 & 1 & 0 \cr
} $$
$$\matrix{
A & B & Y \cr
0 & 0 & 1 \cr
1 & 0 & 1 \cr
0 & 1 & 1 \cr
1 & 1 & 0 \cr
} $$
