Impedance magnitude
= Impedance magnitude
{title2=$|Z|$}
The <impedance magnitude> of a linear <electrical circuit> in sinusoidal steady state is the ratio of <voltage> amplitude to <electric current> amplitude. For <complex impedance> $Z=R+iX$, it is $|Z|=\sqrt{R^2+X^2}$, whereas the dissipative <electrical resistance> is $\operatorname{Re}Z=R$. Measuring only amplitudes does not separately determine $R$ and $X$; a <phase shift> measurement supplies the missing information.