Series RLC behavior relative to resonance: when a series RLC circuit operates at a frequency above its resonant frequency, it behaves most like which simpler series circuit?

Introduction / Context:
Series RLC circuits transition from capacitive to inductive behavior as frequency sweeps through resonance. Recognizing which element “dominates” above or below resonance is crucial for filter design and understanding impedance and phase.

Given Data / Assumptions:

• Ideal series R, L, and C components.
• Single-frequency sinusoidal steady state.
• Resonant frequency fr where X_L = X_C.

Concept / Approach:
Below resonance, capacitive reactance magnitude exceeds inductive reactance (|X_C| > |X_L|), so the net reactance is capacitive; the circuit resembles an RC behavior. At resonance, X_L = X_C and the impedance is purely resistive (Z ≈ R). Above resonance, |X_L| > |X_C|, so the net reactance is inductive; the circuit behaves like an RL network with inductive phase characteristics.

Step-by-Step Solution:

Verification / Alternative check:
Phasor angle of impedance above resonance is positive (inductive), confirming RL-like behavior; below resonance it is negative (capacitive), RC-like; at resonance it is zero (resistive).

Why Other Options Are Wrong:

Common Pitfalls:
Reversing the above/below resonance behaviors; forgetting that at resonance the reactive parts cancel and impedance reduces to R alone.

Final Answer:
series RL circuit.