7. AC power and resonance
Parallel resonance
Formula
Tags
Detail
At parallel resonance |Z| is maximum at ω0.
Explore the idea
Variables
- W
- var
- VA
- RMS (V, A)
- rad
- rad/s
- Ω, H, F.
Conditions
- RMS sinusoids of the same frequency; passive convention.
Intuitive explanation
For “Parallel resonance”: P, Q and S form the power triangle; at resonance net reactance vanishes.
Worked example
If at , and , the total susceptance is zero and there is parallel resonance.
Common mistakes
- taking |S| as P
- forgetting the cos θ factor
- applying series resonance to a parallel tank
Frequently asked questions
- What must be checked before using the Parallel resonance relation?
- Use same-frequency RMS and distinguish P, Q and |S|.
Also known as
- active power, reactive power, power factor, series resonance
Conventions
- W, var, VA or dimensionless
Last reviewed: 2026-09-19