Datasheet

AN4164 Test equipment and measurement of efficiency and light load performance
Doc ID 023660 Rev 1 35/38
observed, the UUT can be considered stable and the measurements can be recorded at the
end of the 5-minute period. If AC input power is not stable over a 5-minute period, the
average power or accumulated energy is measured over time for both AC input and DC
output.
Some wattmeter models allow the measured input power to be integrated in a time range
and then the energy absorbed by the UUT to be measured during the integration time. The
average input power is calculated by dividing it by the integration time itself.