PHYS208 Fundamentals of Physics II

Phasor Animation

This animation is intended to show the relationship between the rotating phasor representing an ac voltage (or current) and the electrical signal that would be observed on an oscilloscope. The rotating arrow represents a phasor quantity; its projection onto the vertical axis, the vertical bar on the phasor diagram, represents the instantaneous value, proportional to the sine of the product of the angular frequency and time. [See note below.] The running sinusoid represents the signal as displayed on an oscilloscope; the intersection of the signal with the vertical axis is the same instantaneous value indicated by the vertical bar.

[phasor animation]

Slow it down...

Note: HRW uses the sine function to represent the time dependence of an ac quantity, thus the projection of the phasor onto the vertical axis. Most other texts use the cosine function, a more natural choice given the relationship between the complex phasor and the Argand diagram, where the projection onto the horizontal axis is the real part of a function.

Last updated Dec. 4, 1997.
Copyright George Watson, Univ. of Delaware, 1997.