To calculate the impedance of an TL series circuit the next formula is used.

Formula 1

Where:
Z is the ciurcuit impedante in ohm (Ω)
XL is the inductive reactance in ohm (Ω)
R is the resistance in ohm (Ω)
Derivated Formulas:
Formula 2

Formula 3

Application Example:
What is the impedance of a circuit formed by a 20-ohm resistor in series with a coil with in impedance of 30 Ω in the frequency of operation?
Data:
R = 20 Ω
XL = 30 Ω
Applying formula 1:

