Sine Curve

—A wave like curve used to represent the changes in strength and direction of an alternating current. The current begins at zero, rises to a maximum, decreases again to zero, and increases to a maximum in the opposite direction, tracing a waving line in which the horizontal distances represent time and the vertical distances represent the varying values of E. M. F. It is called a sine curve because its perpendicular at any point is proportional to the sine of the angle corresponding to that point.