32.5.1 Impedance

The denominator of Equation 32.24 is called the impedance $Z$ of the circuit:

Z = \sqrt{R^{2} + {(X_{​ L} - X_{​ C})}^{2}}

(32.25)

Impedance, like resistance and reactance, is measured in ohms. The circuit’s peak current can be written in terms of the source emf and the circuit impedance as

I = \frac{ε_{0}}{Z}

(32.26)

Equation 32.26 is a compact way to write $I$ , but it doesn’t add anything new to Equation 32.24.