The design of every computer switching power supply that I have seen starts out with the mains power being rectified and fed directly to a capacitor. This results in really bad power factor. I have a 230 watt Startech brand which has an input current rating of 7 amperes at 120 volts, and this is a typical example. I have never seen any attempt by any manufacturer to improve this arrangement. Considering the number of these supplies in use, we are certainly wasting a lot of power heating up the wiring in our homes and offices. Is anyone aware of any company that manufactures computer power supplies with some attention paid to power factor?
Steve Thomas