Apparent power: In alternating-current
power transmission and distribution, the product of the rms
voltage and
amperage.
Note 1: When the applied voltage and the current are in
phase with one another, the apparent power is equal to the
effective power,
i.e., the real power delivered to or consumed by the
load. If the current lags or leads the applied voltage, the apparent power is greater than the effective power.
Note 2: Only effective power, i.e., the real power delivered to or consumed by the load, is expressed in watts. Apparent power is properly expressed only in volt-amperes, never watts.
Source: from Federal Standard 1037C
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