Normally: phasor diagram has points p(x, iy) these points are scalars vector diagram has directional lines starting from a point with arrow ending at another point these lines have both magnitude and direction, i.e. they are not scalars In practice, phasors are used (complex algebra) in circuit analysis and such, where the significance is in resolving the loop/branch currents/voltages. vector diagrams are used (graphical) to visualize relationships between related values, functions, and sometimes to visually resolve some function, such as the resultant into/across a branch. So, in practice, the elements may be the same but the diagrams display and use these elements differently .