Current, Alternating

Usually defined and spoken of as a current flowing alternately in opposite directions. It may be considered as a succe ion of currents, each of short duration and of direction opposite to that of its predece or. It is graphically represented by such a curve as shown in the cut. The horizontal line may denote a zero current, that is no current at all, or may be taken to indicate zero electro-motive force. The curve represents the current, or the corresponding electro-motive forces. The further from the horizontal line the greater is either, and if above the line the direction is opposite to that corresponding to the positions below the line. Thus the current is alternately in opposite directions, has periods of maximum intensity, first in one and then in the opposite sense, and between these, pa ing from one direction to the other, is of zero intensity. It is obvious that the current may rise quickly in intensity and fall slowly, or the reverse, or may rise and fall irregularly. All such phases may be shown by the curve, and a curve drawn to correctly represent these variations is called the characteristic curve of such current. It is immaterial whether the ordinates of the curve be taken as representing current strength or electromotive force. If interpreted as representing electro-motive force, the usual interpretation and best, the ordinates above the line are taken as positive and those below as negative. Synonyms--Reversed Current--Periodic Currents. IMG:8956969607833025625_160F117.JPG: Fig. 117. CHARACTERISTIC CURVE OF ALTERNATING CURRENT. 160   STANDARD ELECTRICAL DICTIONARY.