Article
Article
Phase (periodic phenomena)
Article By:
Galloway, William J. Bolt, Beranek and Newman, Inc., Canoga Park, California.
Last reviewed:August 2020
DOI:https://doi.org/10.1036/1097-8542.505400
The fractional part (portion) of a period through which the time variable of a periodic quantity (alternating electric current, vibration) has moved, as measured at any time instant from an arbitrary time origin. In the case of a sinusoidally varying quantity, the time origin is usually assumed to be the last point at which the value of the quantity was zero, passing from a negative to a positive value. It is customary to choose the origin so that the fractional part of the period is less than unity.
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