Phasor Diagram & Complex Numbers for AC Circuits Analysis

As we saw above, sinusoidal waveform can be defined by three variables (Frequency, Magnitude, Phase). In case then all sources frequency are equal, sinusoidal waveform can be defined by two variables (Magnitude, Phase). Phase and Magnitude defines a phasor(vector) or complex number in polar form. In this case? magnitude is Vector lenght, phase is the angle betwen phasor & x axis.

To determine instantaneous value at the same time, we rotate vector on angle corresponding this time. Projection to Y (j) axis are instantaneous value.