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  • Sir Fredrick - Tuesday, January 11, 2005 - link

    I would have really liked to see them compare the current draw from the wall, to see how the PSUs compare in terms of energy efficiency. Reply
  • Anonymous User - Friday, August 22, 2003 - link

    Switching power supply means the unit can be switched between American 60 Hz, 120 v, and European 50 Hz, 240 v input. Reply
  • Jeff7 - Monday, June 18, 2012 - link

    "Switching power supply" refers to precisely what the article says. The "switch" refers to the manner in which the incoming power is handled, not to a physical component on the unit.
    Plenty of switching power supplies, also called SMPS (switch-mode power supplies), are available without any switches.
    Beside me is a switcher supply that accepts 100-240VAC and puts out 12VDC. There are no switches on it.
    Some of the circuitry I work with uses small switcher supplies, which take 12-36VDC and put out a solid 12VDC output.
    I also work with boosters, which are a kind of switching power supply topology that's capable of putting out a higher voltage than what comes in. These particular ones can take 12VDC and put out about 17.5VDC.
    And, I'm looking at a power supply for integration into a new product, and it can handle anything from 85-264VAC at 47-440Hz. Again, no switches on it.

    Some of the older or cheaper switcher supplies *do* indeed have the selector switch on them to let them accommodate different voltages. But that's not what makes them "switching" power supplies. The name "switch" being the same is simply a coincidence.
    Reply
  • Anonymous User - Friday, August 08, 2003 - link

    :):):):):):):):) Reply
  • Anonymous User - Thursday, August 07, 2003 - link

    Reply
  • Anonymous User - Thursday, August 07, 2003 - link

    PFC, power factor correction, is not just about noise. The square wave shape of current draw of non PFC corrected supplies adds a significant 3rd order harmonics element to the line. This usally is gets diverted by the impedance of power company transformers to flowing in the Neutral line of the power system, which in the past carried almost no current. This nuetral line was installed at a SMALLER size than the mains. There have been buildings burned up in Europe, (which has an older infrastructure) because of this. Also, drawing higher peaks instead of sinusoidal current is less efficient and adds more loss the the wires and transformers, shortening their life and adding more pollution to the world, (ie. more power has to be generated to make up the loss, resulting in more smokestack emissions). Reply

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