What is the magnitude of the impedance of a series RLC circuit at resonance?
The correct answer is D: Approximately equal to circuit resistance. What is the magnitude of the impedance of a series RLC circuit at resonance is approximately equal to circuit resistance. At resonance, XL = XC, so they cancel, leaving only R. For amateur radio operators, this is important for circuit theory. Understanding this helps when working with resonant circuits.
Exam Tip
Series RLC impedance at resonance = approximately equal to circuit resistance. Think 'S'eries 'R'LC at 'R'esonance = 'R'esistance only. At resonance, XL = XC, so they cancel, leaving only R. Not high, not capacitive reactance, not inductive reactance - just resistance.
Memory Aid
"Series RLC impedance at resonance = approximately equal to circuit resistance. Think 'S'eries 'R'LC at 'R'esonance = 'R'esistance. At resonance, XL = XC, so they cancel, leaving only R. Important for circuit theory."
Real-World Application
A series RLC circuit at resonance: The impedance magnitude is approximately equal to the circuit resistance. At resonance, the inductive reactance (XL) and capacitive reactance (XC) are equal and opposite, so they cancel out, leaving only the resistance (R). This is the impedance - approximately equal to resistance.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. High compared to circuit resistance isn't correct - at resonance, impedance equals resistance. High isn't correct.
Option B: Incorrect. Approximately equal to capacitive reactance isn't correct - at resonance, impedance equals resistance. Capacitive reactance isn't the impedance.
Option C: Incorrect. Approximately equal to inductive reactance isn't correct - at resonance, impedance equals resistance. Inductive reactance isn't the impedance.
题目解析
The correct answer is D: Approximately equal to circuit resistance. What is the magnitude of the impedance of a series RLC circuit at resonance is approximately equal to circuit resistance. At resonance, XL = XC, so they cancel, leaving only R. For amateur radio operators, this is important for circuit theory. Understanding this helps when working with resonant circuits.
考试技巧
Series RLC impedance at resonance = approximately equal to circuit resistance. Think 'S'eries 'R'LC at 'R'esonance = 'R'esistance only. At resonance, XL = XC, so they cancel, leaving only R. Not high, not capacitive reactance, not inductive reactance - just resistance.
记忆口诀
Series RLC impedance at resonance = approximately equal to circuit resistance. Think 'S'eries 'R'LC at 'R'esonance = 'R'esistance. At resonance, XL = XC, so they cancel, leaving only R. Important for circuit theory.
实际应用示例
A series RLC circuit at resonance: The impedance magnitude is approximately equal to the circuit resistance. At resonance, the inductive reactance (XL) and capacitive reactance (XC) are equal and opposite, so they cancel out, leaving only the resistance (R). This is the impedance - approximately equal to resistance.
错误选项分析
Option A: Incorrect. High compared to circuit resistance isn't correct - at resonance, impedance equals resistance. High isn't correct. Option B: Incorrect. Approximately equal to capacitive reactance isn't correct - at resonance, impedance equals resistance. Capacitive reactance isn't the impedance. Option C: Incorrect. Approximately equal to inductive reactance isn't correct - at resonance, impedance equals resistance. Inductive reactance isn't the impedance.
知识点
Impedance, Series RLC circuit, At resonance, Approximately equal to circuit resistance
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.