Question

The given graph represents ${\text{V - I}}$ characteristic for a semiconductor device. Which of the following statements is correct?

A. It is ${\text{V - I}}$ characteristic for solar cells where point $A$ represents open circuit voltage and point $B$ Short current.
B. It is for a solar cell and points $A$and $B$represent open circuit voltage and current respectively.
C. It is for a photodiode and points $A$and $B$represent open circuit voltage and current, respectively.
D. It is for a LED and points $A$and $B$represent open circuit voltage and short circuit current respectively.

Answer 1

To determine the correct choice, understand the concepts of V-I characteristic diagram for Photodiode, solar cell and LED. Voltage current relationship for metals and for ohmic conductors is governed by Ohm’s law and thus graph drawn comes out to be a straight line. But in case of semiconductors it is not the case because the working of semiconductors either takes place in forward biasing or in reverse breakdown region.

Complete answer:
Consider the graph of the V-I characteristics,

Understand that, V-I characteristic graph represents the solar cell, at points $A$ the solar cell has the open circuit voltage and current is zero. And at point $B$, there is short circuit current but the voltage becomes zero.

Consider the choice B: The choice $B$ says that, graph represents a solar cell and points $A$ is open circuit voltage and point B is current. Which is an incorrect choice. Because point B represents short circuit current.
Consider the choice C: The choice C says that graph represents photodiode but points $A$ is open circuit voltage and point $B$ is current. Which is incorrect choice .The current becomes constant with respect to the increase in voltage for photodiode and it is reversed bias. Hence the V-I graph represents solar cells.
Consider the choice D: The choice D says that, graph represents LED and points $A$ is open circuit voltage and point $B$ is short circuit current. Which is an incorrect choice. Because LED is forward biased and V-I graph of LED has constant current after a certain voltage.
Consider the choice A: The choice A says that, graph represents the solar cell but points $A$ is open circuit voltage and point $B$ is short circuit current. Which is the correct choice.

Therefore, the correct choice is option A.

Note: : The V-I characteristic graph represents solar cells, at point A the solar cell has the open circuit voltage and current is zero. And at point B, there is short circuit current but the voltage becomes zero. Open circuit means that the component is attached and if it is written that the circuit is short circuited then we remove all the components in that arm or branch of the given circuit.