Why does a PN-junction diode not conduct current when reverse biased?
The correct answer is C: Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region. Why does a PN-junction diode not conduct current when reverse biased is that holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region. Reverse bias widens the depletion region, preventing conduction. For amateur radio operators, this is important for semiconductor knowledge. Understanding this helps when working with diodes.
Exam Tip
PN-junction reverse bias = holes and electrons separated, depletion region widens. Think 'R'everse 'B'ias = 'R'epels carriers, 'B'roadens depletion region. Reverse bias widens the depletion region, preventing conduction. Not P-type only, not N-type only, not combining to insulator - just separation widening depletion region.
Memory Aid
"PN-junction reverse bias = holes and electrons separated, depletion region widens. Think 'R'everse 'B'ias = 'W'idens depletion region. Reverse bias widens the depletion region, preventing conduction. Important for semiconductor knowledge."
Real-World Application
A PN-junction diode reverse biased: It doesn't conduct current because holes in P-type material and electrons in N-type material are separated by the applied voltage, widening the depletion region. The wider depletion region prevents current flow. This is why it doesn't conduct - separation widening depletion region.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Only P-type conducting isn't the reason - reverse bias widens depletion region, preventing conduction. P-type only isn't the reason.
Option B: Incorrect. Only N-type conducting isn't the reason - reverse bias widens depletion region, preventing conduction. N-type only isn't the reason.
Option D: Incorrect. Holes and electrons combining to convert diode to insulator isn't the reason - reverse bias widens depletion region. Combining to insulator isn't the reason.
题目解析
The correct answer is C: Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region. Why does a PN-junction diode not conduct current when reverse biased is that holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region. Reverse bias widens the depletion region, preventing conduction. For amateur radio operators, this is important for semiconductor knowledge. Understanding this helps when working with diodes.
考试技巧
PN-junction reverse bias = holes and electrons separated, depletion region widens. Think 'R'everse 'B'ias = 'R'epels carriers, 'B'roadens depletion region. Reverse bias widens the depletion region, preventing conduction. Not P-type only, not N-type only, not combining to insulator - just separation widening depletion region.
记忆口诀
PN-junction reverse bias = holes and electrons separated, depletion region widens. Think 'R'everse 'B'ias = 'W'idens depletion region. Reverse bias widens the depletion region, preventing conduction. Important for semiconductor knowledge.
实际应用示例
A PN-junction diode reverse biased: It doesn't conduct current because holes in P-type material and electrons in N-type material are separated by the applied voltage, widening the depletion region. The wider depletion region prevents current flow. This is why it doesn't conduct - separation widening depletion region.
错误选项分析
Option A: Incorrect. Only P-type conducting isn't the reason - reverse bias widens depletion region, preventing conduction. P-type only isn't the reason. Option B: Incorrect. Only N-type conducting isn't the reason - reverse bias widens depletion region, preventing conduction. N-type only isn't the reason. Option D: Incorrect. Holes and electrons combining to convert diode to insulator isn't the reason - reverse bias widens depletion region. Combining to insulator isn't the reason.
知识点
PN-junction diode, Not conduct current, Reverse biased, Holes and electrons separated, Widening depletion region
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.