Phase

Phase refers to the temporal relationship of two (or more) sinusoidal alternating current signals of the same frequency. The relationship between two such signals is measured in 'degrees'; degrees being a measure used for sinusoidal waveforms, with 360 degrees being one complete cycle.

If two signals reach their maximum positive voltage at the same point in time, they are said to be 'in phase'. In phase signals are 0 degrees apart; if a second signal reaches its maximum negative voltage at the same time as another reaches its maximum positive voltage, they are said to be 180 degrees apart, or 'maximally out of phase'.

See also

• Three-phase power
• Overpowered‎ - a 'phased' story