Hi all sifus like goldfries,

I have some confusion on power efficiency and power factor.

for the sake of example, if my PC is drawing 500Watts constantly, lets say my PSU is 80% efficiency, i will draw 600watts from AC then convert it into 500watts DC right. then if lets say my PSU power factor is only 0.5, then i will draw 1200 apparent power (in form of VA) from mains, though i will be only using 600watts as work done.

so in TNB point of view, TNB only charges for watts or work done, therefore only charge me the 600watts, and since residential rate doesnt have Power Factor surcharge, im done with that. but if im on commercial, the charging will be 600 watts + 3% surcharge (according to TNB, less than 0.85 PF will get 3% surcharge).

and in short, Power Efficiency is used for DC, while Power Factor is used for AC to gauge the efficiency

am i correct?

Thanks

This post has been edited by Christopher_LKL: Jan 29 2016, 10:32 AM

Depends on the Load of the system