Question

Given below are V versus I graphs for different types of p-n junction diodes marked A, B, C, and D.

The correct sequence of graphs corresponding to forward biased p-n junction; Zener
diode; Photo diode and Solar cell in order is _________.
Fill in the blank with the correct answer from the options given below.

• A. (A), (C), (B), (D)
• B. (D), (C), (A), (B)
• C. (B), (A), (D), (C)
• D. (C), (B), (D), (A)

Answer 1

The Correct Option is B

In this problem, we need to identify which V-I graph corresponds to each type of p-n junction diode: forward-biased p-n junction, Zener diode, photodiode, and solar cell. Let's analyze the characteristics of each device to find the correct order: 

• Forward-biased p-n junction diode: This will have an exponential V-I relationship where the current increases rapidly after exceeding a threshold voltage (forward voltage).
• Zener diode: Operates in reverse bias, and the V-I graph will show a sharp increase in reverse current after the breakdown voltage is reached.
• Photodiode: Typically operates in reverse bias. The current (reverse current) increases slightly with an increase in reverse voltage. Photocurrent varies with light intensity.
• Solar cell: Operates in the fourth quadrant where light generates a current even when voltage is negative, resembling the graph of a voltage source.

Given these descriptions, let's match with the graph characteristics:

1. The forward-biased p-n junction will have a graph showing a steep rise after a certain positive voltage.
2. The Zener diode’s characteristic curve will show a sharp rise in reverse bias at the breakdown voltage.
3. The photodiode graph will show limited current increase in reverse bias and dependency on light intensity.
4. The solar cell will exhibit characteristics akin to a current generator when exposed to light.

From the options: (D), (C), (A), (B), let's match them:

D: Forward-biased p-n junction diode

C: Zener diode

A: Photodiode

B: Solar cell

This matches our analysis, thus the correct answer is: (D), (C), (A), (B).