Two p-n junction diodes D₁ and D₂ are connected as shown in figure. A and B are input signals and C is the output. The given circuit will function as $a ____.$

Question

Two p-n junction diodes D₁ and D₂ are connected as shown in figure. A and B are input signals and C is the output. The given circuit will function as a ____.

G1 Physics · Accepted Answer

The output node C is connected to +5 V through resistor R. The two diodes are arranged so that if either input A or input B is at logic 0, the corresponding diode becomes forward biased and pulls the output node C to logic 0. Therefore: • If A = 0 or B = 0, then C = 0. • Only when A = 1 and B = 1 are both diodes non-conducting, allowing resistor R to pull C to logic 1. Thus the truth table is that of an AND gate: C = A·B. Correct option: D.