When an alternator produces AC voltage, the voltage switches polarity over time, but does so in a very particular manner. When graphed over time, the “wave” traced by this voltage of alternating polarity from an alternator takes on a distinct shape, known as a sine wave: Figure below
Graph of AC voltage over time (the sine wave)
In the
voltage plot from an electromechanical alternator, the change from
one polarity to the other is a smooth one, the voltage level changing
most rapidly at the zero (“crossover”) point and most slowly at
its peak. If we were to graph the trigonometric function of “sine”
over a
