Question

A certain p-n junction, having a depletion region of width 20mm was found to have a breakdown voltage of 100V. If the width of the depletion region is reduced to 1 mm during its production, then it can be used as a Zener diode for voltage regulation of

• A. 15V
• B. 5V
• C. 7.5V
• D. 2000V

Hint:

Remember that for Zener diodes, the breakdown voltage is inversely proportional to the width of the depletion region. Reducing the width increases the breakdown voltage.

Answer 1

The Correct Option is B

Step 1: Understanding the relationship.
In a Zener diode, the breakdown voltage is inversely proportional to the width of the depletion region. The breakdown voltage \( V \) can be related to the width of the depletion region \( W \) by the equation: \[ V_1 W_1 = V_2 W_2 \] Where: - \( V_1 = 100V \) and \( W_1 = 20 \, \text{mm} \) - \( W_2 = 1 \, \text{mm} \) (new width)
Step 2: Apply the relation.
Substitute the known values into the equation to solve for \( V_2 \): \[ 100 \times 20 = V_2 \times 1 \] \[ V_2 = 100 \times 20 = 5V \]
Step 3: Conclusion.
The Zener diode will have a breakdown voltage of 5V when the depletion region width is reduced to 1 mm. Therefore, the correct answer is (2) 5V.