The following formula is used to find the impedance of a capacitor and an inductor wired in series.
Formula 1
Z = Xc – XL
Where:
Z is the impedance in ohm (Ω)
Xc is the capacitive reactance in ohm (Ω)
XL is the inductive reactance in ohm (Ω)
Derivated Formulas:
Formula 2
Xc = XL + Z
Formula 3
XL = Xc + Z
Note:
If Xc is larger tan XLÇ the circuit has a capacitive characteristic.
If Xc is smaller than XL the circuit has a inductive characteristic
If Xc = Xl the circuit is resonant in the operation frequency (see resonance formula for more details)
Application Example:
A capacitor with a capacitive reactance of 3 Ω is wired in series with a coil having an inductive reactance of 4 Ω in the same circuit. Calculate the impedance presented by this association.
Data:
Xc = 3 Ω
XL = -4 Ω
Z = ?
Applying formula 1:
Z = 3 – 4 = -1 ohm (inductive impedance)
