Quality factor (Q) of a resonant circuit — is it equal to the ratio of true power to apparent power (i.e., the power factor)?

Introduction / Context:
Quality factor and power factor are distinct concepts that apply to different aspects of AC and resonant circuit behavior. Confusing them leads to errors in filter design and bandwidth estimation.

Given Data / Assumptions:

• Sinusoidal steady-state conditions.
• Q refers to resonant circuit quality factor, not reactive power symbol Q in power systems.
• PF denotes power factor P/S.

Concept / Approach:

Power factor is PF = P / S = cos(phi). Quality factor of a simple inductor or capacitor at a given frequency equals reactance divided by resistance (Q = X / R). For a resonant network, Q relates stored reactive energy to energy dissipated per cycle and also to bandwidth via Q = f0 / BW.

Step-by-Step Solution:

Verification / Alternative check:

Bandwidth relation: Q = f0 / BW shows Q determines selectivity, a property unrelated to PF. Devices can have high Q but low PF depending on the load and phase angle.

Why Other Options Are Wrong:

• Limiting statements (parallel, series, high-Q) do not change the definition of Q.
• Negligible losses increase Q but do not convert Q into PF.

Common Pitfalls:

Confusing the symbol Q for reactive power in power engineering with quality factor Q in resonance theory. Always check context.

Final Answer:

False