What property of an LED's semiconductor material determines its forward voltage drop?
The correct answer is B: Band gap. What property of an LED's semiconductor material determines its forward voltage drop is band gap. The band gap determines the forward voltage of an LED. For amateur radio operators, this is important for LED knowledge. Understanding this helps when working with LEDs.
Exam Tip
LED forward voltage determined by = band gap. Think 'L'ED 'F'orward 'V'oltage = 'B'and 'G'ap. The band gap determines the forward voltage of an LED. Not intrinsic resistance, not junction capacitance, not junction depth - just band gap.
Memory Aid
"LED forward voltage determined by = band gap. Think 'L'ED = 'B'and 'G'ap. The band gap determines the forward voltage of an LED. Important for LED knowledge."
Real-World Application
An LED's forward voltage drop: It's determined by the band gap of the LED's semiconductor material. Different materials have different band gaps, resulting in different forward voltages (e.g., red LEDs ~1.8V, blue LEDs ~3.5V). This is the property - band gap.
Key Concepts
Why Other Options Are Wrong
Option A (Intrinsic resistance): Incorrect. Intrinsic resistance isn't what determines forward voltage - band gap is. Intrinsic resistance isn't the property.
Option C (Junction capacitance): Incorrect. Junction capacitance isn't what determines forward voltage - band gap is. Junction capacitance isn't the property.
Option D (Junction depth): Incorrect. Junction depth isn't what determines forward voltage - band gap is. Junction depth isn't the property.
题目解析
The correct answer is B: Band gap. What property of an LED's semiconductor material determines its forward voltage drop is band gap. The band gap determines the forward voltage of an LED. For amateur radio operators, this is important for LED knowledge. Understanding this helps when working with LEDs.
考试技巧
LED forward voltage determined by = band gap. Think 'L'ED 'F'orward 'V'oltage = 'B'and 'G'ap. The band gap determines the forward voltage of an LED. Not intrinsic resistance, not junction capacitance, not junction depth - just band gap.
记忆口诀
LED forward voltage determined by = band gap. Think 'L'ED = 'B'and 'G'ap. The band gap determines the forward voltage of an LED. Important for LED knowledge.
实际应用示例
An LED's forward voltage drop: It's determined by the band gap of the LED's semiconductor material. Different materials have different band gaps, resulting in different forward voltages (e.g., red LEDs ~1.8V, blue LEDs ~3.5V). This is the property - band gap.
错误选项分析
Option A (Intrinsic resistance): Incorrect. Intrinsic resistance isn't what determines forward voltage - band gap is. Intrinsic resistance isn't the property. Option C (Junction capacitance): Incorrect. Junction capacitance isn't what determines forward voltage - band gap is. Junction capacitance isn't the property. Option D (Junction depth): Incorrect. Junction depth isn't what determines forward voltage - band gap is. Junction depth isn't the property.
知识点
LED's semiconductor material, Property, Determines forward voltage drop, Band gap
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.