$$Let\quad \vec { Z } =R+Xj$$(adsbygoogle = window.adsbygoogle || []).push({});

If X>0,then the impedance is lagging (current lags behind voltage).If X<0,then the impedance is leading (current leads voltage or more accurately, voltage lags behind current). If X=0, the current and voltage are in phase and the load is called purely real. If x≠0, the current and voltage are not in phase and the load is called complex.

Some load is purely real if and only if the load is purely resistive.

Some load is purely imaginary if and only if the load is purely reactive.

Questions:

1. Does it make physical sense for a load to be purely imaginary or purely reactive?

2. How do we know that when X>0, current lags behind voltage and not the other way around?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Do I understand impedance correctly? Can anyone fact check my post?

**Physics Forums | Science Articles, Homework Help, Discussion**