Division Accuracy
Measurements made with these procedures must in all cases have an accuracy of 5 % or better, though manufacturers will usually achieve better than this. Test procedures may specify greater accuracy than 5 % for some measurements. With knowledge of the power levels of current imaging products and the meters available, manufacturers can calculate the maximum error based on the reading and the range utilised for the reading. For measurements of 0.50 W or less, the required accuracy is 0.02 W.
Notes on Division (b)
Footnotes
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True power is defined as (volts)x(amps)x(power factor), and is typically reported as Watts. Apparent power is defined as (volts)x(amps), and is usually expressed in terms of VA or volt-amps. The power factor for equipment with switching power supplies is always less than 1.0, so true power is always less than apparent power. Accumulated energy measurements sums power measurements over a period of time and so also need to be based on measurements of true power.
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IEC 62301 — Household Electrical Appliances — Measurement of Standby Power 2005.