The purpose of this whitepaper is to establish a standardized method that can be used to measure active-mode efficiency and no-load power consumption of AC-DC power supply, according to energy efficiency standards. In this whitepaper, active-mode efficiency is the ratio, expressed as a percentage, of the total real output power produced by a power supply to the real input power (AC) required to produce it. No-load consumption is defined as the wattage of real power (AC) consumed by a power supply operating in no-load condition.