Question

Two similar $p-n$ junctions can be connected in three different ways, as shown in the figures. The connections across which the potential difference is the same are

• A. Circuits $\text{(a) and (b)}$
• B. Circuits $\text{(b) and (c)}$
• C. Circuits $\text{(a) and (c)}$
• D. All the circuits

Answer 1

The correct option is B Circuits $\text{(b) and (c)}$

In the circuit $\left(\text{a}\right)$, the first diode is forward biased while the second is reversed biased, so the resistance of the both the diodes will be different,

Therefore, the potential difference across them will be different.

In the circuit $\left(\text{b}\right)$, both diodes are forward biased, so the resistance of the both the diodes will be same,

Therefore, the potential difference across them will be the same.

In the circuit $\left(\text{c}\right)$, both diodes are reverse biased, so the resistance of the both the diodes will be same,

Therefore, the potential difference across them will be the same.

Hence, option $\left(\text{B}\right)$ is correct.