Deep Dive: E5A04
The correct answer is A: Approximately equal to circuit resistance. What is the magnitude of the impedance of a parallel RLC circuit at resonance is approximately equal to circuit resistance. At parallel resonance, impedance is maximum and approximately equal to R. For amateur radio operators, this is important for circuit theory. Understanding this helps when working with resonant circuits.
Why Other Answers Are Wrong
Option B: Incorrect. Approximately equal to inductive reactance isn't correct - at parallel resonance, impedance equals resistance. Inductive reactance isn't the impedance. Option C: Incorrect. Low compared to circuit resistance isn't correct - at parallel resonance, impedance is high (equal to R). Low isn't correct. Option D: Incorrect. High compared to circuit resistance isn't correct - at parallel resonance, impedance equals resistance. High isn't correct.
Exam Tip
Parallel RLC impedance at resonance = approximately equal to circuit resistance. Think 'P'arallel 'R'LC at 'R'esonance = 'R'esistance. At parallel resonance, impedance is maximum and approximately equal to R. Not inductive reactance, not low, not high - just approximately equal to resistance.
Memory Aid
Parallel RLC impedance at resonance = approximately equal to circuit resistance. Think 'P'arallel 'R'LC at 'R'esonance = 'R'esistance. At parallel resonance, impedance is maximum and approximately equal to R. Important for circuit theory.
Real-World Example
A parallel RLC circuit at resonance: The impedance magnitude is approximately equal to the circuit resistance. At parallel resonance, the impedance is maximum and approximately equal to R. This is the impedance - approximately equal to resistance.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E5A
Reference: 2024-2028 Question Pool · E5 - Electrical Principles
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5A topic.