Semiconductor Electronics question for JEE Main (JEE Main 2018 (15 Apr, Shift 2)), with solution

Answer: (C) $\begin{array}{ccc} x & y & z \\ 0 & 0 & 1 \\ 0 & 1 & 1 \\ 1 & 0 & 1 \\ 1 & 1 & 1 \end{array}$

Reading the circuit:

- Upper AND gate: inputs $x$ and $y$, output $xy$.
- Lower AND gate: inputs $\bar x$ (through the NOT gate) and $y$, output $\bar xy$.
- NAND gate: $z = \overline{(xy)(\bar xy)}$.

Since $x\bar x = 0$, the product $(xy)(\bar xy)$ is always $0$, so
$$z = \bar 0 = 1$$
for every input. The output column is $1, 1, 1, 1$: option (3).

Solution by Sreeraj P, M.Sc Physics