The $$I - V$$ characteristics of an electronic device shown in the figure. The device is:

Here is the formatted breakdown of the question and its solution.

Problem Statement

The $$I\text{-}V$$ characteristics of an electronic device are shown in the figure. The device is:

• (1) a solar cell
• (2) a transistor which can be used as an amplifier
• (3) a Zener diode which can be used as a voltage regulator
• (4) a diode which can be used as a rectifier
• When a positive voltage is applied ($$V > 0$$), the current increases exponentially after a certain threshold voltage. This is typical behavior for any semiconductor junction diode.
• When a negative voltage is applied ($$V < 0$$), only a very small, almost constant reverse saturation current flows (measured in microamperes, $$\mu\text{A}$$).
• As the negative voltage increases further, the current suddenly drops sharply down at a specific sharp knee voltage. This is known as Zener Breakdown.
• Once breakdown occurs, the voltage across the device remains practically constant over a wide range of reverse currents.
• This unique property makes the Zener diode ideal for maintaining a stable output voltage in power supplies, functioning as a voltage regulator.

Detailed Explanation

The given graph plots current ($$I$$) against voltage ($$V$$) for an electronic component. We can identify the device by breaking down the distinct regions of the curve:

1. Forward Bias Region (First Quadrant)

2. Reverse Bias Region (Third Quadrant)

3. Application as a Voltage Regulator

Correct Answer

The correct option is (3) a Zener diode which can be used as a voltage regulator.