How is the efficiency of an RF power amplifier determined?
The correct answer is B: Divide the RF output power by the DC input power. How the efficiency of an RF power amplifier is determined is to divide the RF output power by the DC input power. Efficiency = (RF output / DC input) × 100%. For amateur radio operators, this is a fundamental amplifier calculation. Understanding this helps when evaluating amplifier performance.
Exam Tip
RF amplifier efficiency = RF output / DC input. Think 'E'fficiency = 'E'ffective output / 'E'nergy input. Divide RF output power by DC input power. Not DC/DC, not RF input/reciprocal, not RF+DC - just RF output / DC input.
Memory Aid
"RF amplifier efficiency = RF output / DC input. Think 'E'fficiency = 'E'ffective output / 'E'nergy input. Divide RF output power by DC input power. Standard efficiency calculation."
Real-World Application
An RF power amplifier: DC input = 200 watts, RF output = 100 watts. Efficiency = 100 / 200 = 0.5 = 50%. The amplifier converts 50% of DC input power to RF output power. This is how amplifier efficiency is calculated.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Efficiency isn't DC input divided by DC output - that would be greater than 1, which doesn't make sense. Efficiency is output divided by input.
Option C: Incorrect. Efficiency isn't RF input multiplied by reciprocal of RF output - that's not the efficiency formula. Efficiency is output divided by input.
Option D: Incorrect. Efficiency isn't RF input added to DC output - that's not how efficiency is calculated. Efficiency is output divided by input.
题目解析
The correct answer is B: Divide the RF output power by the DC input power. How the efficiency of an RF power amplifier is determined is to divide the RF output power by the DC input power. Efficiency = (RF output / DC input) × 100%. For amateur radio operators, this is a fundamental amplifier calculation. Understanding this helps when evaluating amplifier performance.
考试技巧
RF amplifier efficiency = RF output / DC input. Think 'E'fficiency = 'E'ffective output / 'E'nergy input. Divide RF output power by DC input power. Not DC/DC, not RF input/reciprocal, not RF+DC - just RF output / DC input.
记忆口诀
RF amplifier efficiency = RF output / DC input. Think 'E'fficiency = 'E'ffective output / 'E'nergy input. Divide RF output power by DC input power. Standard efficiency calculation.
实际应用示例
An RF power amplifier: DC input = 200 watts, RF output = 100 watts. Efficiency = 100 / 200 = 0.5 = 50%. The amplifier converts 50% of DC input power to RF output power. This is how amplifier efficiency is calculated.
错误选项分析
Option A: Incorrect. Efficiency isn't DC input divided by DC output - that would be greater than 1, which doesn't make sense. Efficiency is output divided by input. Option C: Incorrect. Efficiency isn't RF input multiplied by reciprocal of RF output - that's not the efficiency formula. Efficiency is output divided by input. Option D: Incorrect. Efficiency isn't RF input added to DC output - that's not how efficiency is calculated. Efficiency is output divided by input.
知识点
RF power amplifier efficiency, RF output power, DC input power, Efficiency calculation
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.