Editing Q factor (section)

=== Individual reactive components ===

The {{mvar|Q}} of an individual reactive component depends on the frequency at which it is evaluated, which is typically the resonant frequency of the circuit that it is used in. The {{mvar|Q}} of an inductor with a series loss resistance is the {{mvar|Q}} of a resonant circuit using that inductor (including its series loss) and a perfect capacitor.<ref name=dipaolo>
{{cite book
 |title       = Networks and Devices Using Planar Transmission Lines
 |first       = Franco
 |last        = Di Paolo
 |publisher   = CRC Press
 |year        = 2000
 |isbn        = 9780849318351
 |pages       = 490–491
 |url         = https://books.google.com/books?id=z9CsA1ZvwW0C&pg=PA489
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20180511181437/https://books.google.com/books?id=z9CsA1ZvwW0C&pg=PA489
 |archive-date = 2018-05-11
}}</ref>

<math display="block">Q_L = \frac{X_L}{R_L}=\frac{\omega_0 L}{R_L}</math>

where:
* {{math|''ω''<sub>0</sub>}} is the resonance frequency in radians per second;
* {{mvar|L}} is the inductance;
* {{mvar|X<sub>L</sub>}} is the [[inductive reactance]]; and
* {{mvar|R<sub>L</sub>}} is the series resistance of the inductor.

The {{mvar|Q}} of a capacitor with a series loss resistance is the same as the {{mvar|Q}} of a resonant circuit using that capacitor with a perfect inductor:<ref name=dipaolo/>

<math display="block">Q_C = \frac{-X_C}{R_C}=\frac{1}{\omega_0 C R_C}</math>

where:
* {{math|''ω''<sub>0</sub>}} is the resonance frequency in radians per second;
* {{mvar|C}} is the capacitance;
* {{mvar|X<sub>C</sub>}} is the [[capacitive reactance]]; and
* {{mvar|R<sub>C</sub>}} is the series resistance of the capacitor.

In general, the {{mvar|Q}} of a resonator involving a series combination of a capacitor and an inductor can be determined from the {{mvar|Q}} values of the components, whether their losses come from series resistance or otherwise:<ref name=dipaolo/>

<math dislpay="block"> Q = \frac{1}{\frac{1}{Q_L} + \frac{1}{Q_C}} </math>