Q 12-14-129JEE MainJEE Main 2021 (31 Aug, Shift 2)Easy
If $V_A$ and $V_B$ are the input voltages (either $5$ V or $0$ V) and $V_0$ is the output voltage then the two gates represented in the following circuits $A$ and $B$ are:
Answer: (A) OR and NOT Gate
Circuit $A$: if either input is at $5$ V, its diode conducts and $V_0 \approx 5$ V; only when both are $0$ V is $V_0 = 0$. This is an OR gate.
Circuit $B$: with $V_B = 5$ V the transistor saturates and $V_0 \approx 0$; with $V_B = 0$ it is cut off and $V_0 = 5$ V. This is a NOT gate.
Solution by Sreeraj P, M.Sc Physics