JEE Main · 2023 · 13 Apr 2023 · Shift 2 · Semiconductors

A NAND gate produces output $0$ only when both of its inputs are $1$ at the same instant, and output $1$ in every other case. Comparing the two input waveforms interval by interval, inputs $A$ and $B$ are simultaneously high in only two of the time intervals; in all the other intervals at least one input is low. The output therefore drops to low in exactly those two intervals where both inputs are high and stays high throughout every remaining interval.