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

The objective is to associate each V-I graph with a specific p-n junction diode type: forward-biased p-n junction, Zener diode, photodiode, and solar cell. We will examine the behavior of each device to determine the correct graphical representation:

• Forward-biased p-n junction diode: Exhibits an exponential V-I relationship, with current increasing sharply above a threshold (forward) voltage.
• Zener diode: Operates in reverse bias. Its V-I graph shows a rapid increase in reverse current once the breakdown voltage is reached.
• Photodiode: Typically functions in reverse bias. The reverse current shows a minor increase with rising reverse voltage and is dependent on light intensity.
• Solar cell: Operates in the fourth quadrant. Light generates a current even with a negative voltage, similar to the characteristic of a voltage source.

Based on these descriptions, let's match them to the graphical characteristics:

1. The graph for a forward-biased p-n junction will display a steep current rise beyond a specific positive voltage.
2. The Zener diode's characteristic curve will demonstrate a sharp increase in reverse current at its breakdown voltage.
3. The photodiode graph will show a limited current increase under reverse bias, with variations tied to light intensity.
4. The solar cell, when illuminated, will behave like a current generator.

Considering the provided options: (D), (C), (A), (B), we can make the following matches:

D: Forward-biased p-n junction diode

C: Zener diode

A: Photodiode

B: Solar cell

This alignment confirms our analysis, leading to the correct answer: (D), (C), (A), (B).