Electric power

The instantaneous rate of energy transfer through a circuit port is $P(t)=V(t)I(t)$, with positive electric current entering the positive voltage terminal for the passive sign convention. Peak phasors in sinusoidal steady state give $⟨P⟩=\frac{1}{2}\mathrm{Re}(\tilde{V}{\tilde{I}}^{\ast })$. The factor $1/2$ is absent for root mean square phasors.