Question

A diode is connected in parallel with a resistance as shown in Figure. The most probable current (\( I \)) - voltage (\( V \)) characteristic is:

• A. A graph with a smooth curve rising steeply for positive voltage
• B. A straight line with a slope for positive voltage
• C. A graph showing a small hump before a steep rise for positive voltage
• D. A sharply increasing graph after a certain voltage threshold

Hint:

When analyzing a diode in a circuit, remember that the diode has a non-linear \( I-V \) characteristic, which results in rapid current increases once the voltage exceeds the threshold.

Answer 1

The Correct Option is D

Step 1: Understanding the Behavior of a Diode
- A diode typically has a non-linear \( I-V \) characteristic.
- For negative voltage (reverse bias), the current is close to zero until the diode reaches the breakdown voltage.
- For positive voltage (forward bias), the current increases rapidly after the threshold voltage (usually around 0.7 V for silicon diodes).
Step 2: Diode-Resistor Parallel Circuit
In a parallel circuit with a resistor and a diode, the current-voltage characteristic will be influenced by both components:
1. The resistor will cause a linear increase in current with voltage.
2. The diode will show a non-linear characteristic, initially having very small current, but rapidly increasing as the forward voltage crosses a threshold.
Step 3: Analyzing the Graphs
- Option (A): A smooth curve rising steeply for positive voltage matches the typical behavior of a diode, but the curve might be too idealized for a parallel resistor.
- Option (B): A straight line is not correct because a diode does not have a linear \( I-V \) characteristic.
- Option (C): A graph with a small hump suggests a more complex interaction, which could happen in a more complicated circuit setup but is less common for a simple parallel diode-resistor setup.
- Option (D): A sharply increasing graph after a certain voltage threshold is the most likely behavior for the diode, especially after the threshold voltage is crossed.
Step 4: Conclusion The most probable current-voltage characteristic for a diode connected in parallel with a resistor is represented by a graph that starts with a very small current and sharply increases after a certain voltage threshold is crossed.
Thus, the correct answer is:
\[ \boxed{(D)} \]