Question

Resistance of an ideal p-n junction diode in reverse bias is:

• A. zero
• B. infinite
• C. in between zero and infinite
• D. none of these

Hint:

In reverse bias, an ideal p-n junction diode does not conduct, and its resistance is considered infinite.

Answer 1

The Correct Option is B

A p-n junction diode consists of two semiconductor regions: a p-type (positive) region and an n-type (negative) region, which are brought into contact to form a junction. In forward bias, the p-side is connected to the positive terminal and the n-side to the negative terminal, which allows current to flow. In reverse bias, the p-side is connected to the negative terminal and the n-side to the positive terminal, which theoretically prevents current from flowing. However, for an ideal p-n junction diode in reverse bias: 1. Reverse Bias Behavior:
- In reverse bias, no current flows through the ideal diode under normal conditions.
- The ideal diode has no leakage current (i.e., no reverse saturation current) in this condition.
2. Ideal Diode:
- An ideal diode is assumed to have no internal resistance when forward biased and infinite resistance when reverse biased.
- Since no current can flow through the diode in reverse bias, the resistance of the ideal p-n junction diode is considered infinite.
\[ R = \frac{V}{I} \] Since \( I = 0 \) in reverse bias for an ideal diode, the resistance is considered infinite.