Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E5A
E5A09E5A

How is the Q of an RLC parallel resonant circuit calculated?

Deep Dive: E5A09

The correct answer is C: Resistance divided by the reactance of either the inductance or capacitance. How is the Q of an RLC parallel resonant circuit calculated is resistance divided by the reactance of either the inductance or capacitance. Q = R/X for parallel circuits. For amateur radio operators, this is important for circuit calculations. Understanding this helps when calculating Q.

Why Other Answers Are Wrong

Option A: Incorrect. Reactance divided by resistance isn't correct - for parallel circuits, Q = R/X. Reactance/resistance is wrong. Option B: Incorrect. Reactance multiplied by resistance isn't correct - for parallel circuits, Q = R/X. Reactance×resistance is wrong. Option D: Incorrect. Reactance of inductance multiplied by reactance of capacitance isn't correct - for parallel circuits, Q = R/X. XL×XC is wrong.

Exam Tip

Parallel RLC Q = resistance divided by reactance of either L or C. Think 'P'arallel 'Q' = 'R'/'X'. Q = R/X for parallel circuits. Not X/R, not X×R, not XL×XC - just R/X.

Memory Aid

Parallel RLC Q = resistance divided by reactance of either L or C. Think 'P'arallel 'Q' = 'R'/'X'. Q = R/X for parallel circuits. Important for circuit calculations.

Real-World Example

The Q of an RLC parallel resonant circuit: It's calculated as resistance divided by the reactance of either the inductance or capacitance. Q = R/X, where X is XL or XC (they're equal at resonance). This is the calculation - R/X for parallel circuits.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E5A

Reference: 2024-2028 Question Pool · E5 - Electrical Principles

Key Concepts

Q of RLC parallel resonant circuit Calculated Resistance divided by reactance Inductance or capacitance

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5A topic.