
The Sinusoidal AC Waveform The most common AC waveform is a sine (or sinusoidal)
waveform.
The vertical axis represents the amplitude
of the AC current or voltage, in amperes or volts.
The horizontal axis represents the angular
displacement of the waveform. The units can be degrees or radians.

The
sine waveform is accurately represented by the sine function of plane trigonometry:
y = rsinq
where:
 y = the instantaneous amplitude
 r = the maximum amplitude
 q = the
horizontal displacement
