JEE MainPhysicsSemiconductors
In a digital circuit, two inputs A and B are connected to the N-sides (cathodes) of two ideal diodes D₁ and D₂ respectively. The P-sides (anodes) of both diodes are tied together at a common node P . This node P is connected to a +5 V supply through a resistor R . The voltage at node P is then fed simultaneously into both the inputs of a NOR gate to produce the final output Y . Assuming 0 V corresponds to logic 0 and
Options
- AAND gate
- BNAND gate
- CNOR gate
- DOR gate
Correct answer
B. NAND gate
Step-by-step solution
First, we analyze the diode circuit. The inputs A and B are connected to the N-sides of the diodes, and the P-sides are pulled up to +5 V (logic 1 ) via resistor R . If either input A or B is at 0 V (logic 0 ), the corresponding diode becomes forward-biased and acts as a short circuit (ideal diode). This pulls the voltage at node P down to 0 V (logic 0 ). If both inputs A and B are at +5 V (logic 1 ), both diodes are reverse-biased and act as open circuits. No current flows through R , so node P remains at +5 V (lo