Phasor

• Complex number that represents amplitude/magnitude and phase of a sinusoidal wave with frequency $\omega$
• So we can convert, for example $$
  \begin{align}
  v(t) & =V_{a}\cos(\omega t+\theta) \
  & =\Re \left{ V_{a}e^{j(\omega t+\theta)} \right} \
  & =\Re \left{ V_{a}e^{j\theta}e^{j\omega t} \right}
  \end