What is a 'switching' PSU?

I believe it will automatically switch between 115V and 230V operation (or is it 120V and 240V)

it might be so they dont have to make different models for us/european markets, with eu using 240v. When i was younger (about 8 ) i wondered what the switch did on a computer my dad brought me home from work, so i switched it. BANG! Oh well, thats the way i learn

I have several power supplies that have a switch labeled 115V and 230V, hence the numbers I provided.

The lack of the switch on the new power supply suggests that circuitry is present to automatically detect and adjust to 115V or 230V curcuits.

The 'standard' however is 110V and 220V.

Notebook power supplies have had the automatic switching for quite some time (a few years)

You know, a simple Googling (or Wikipedia search) provides a lot of information:

http://en.wikipedia.org/wiki/Switching_power_supply

There's your answer.

I don't think you paid enough attention to the article. The switch on the back of a PSU to control input voltage has nothing to do with the PSU being a "switching" unit or not. Non-switching PSUs can accept multiple input voltages too.

I have no idea why someone would mention "switching" in the ad copy like that 2 dozen times. ALL modern computer power supplies are switchers. ALL. Well, I've never seen anything but!

Switching power supplies do indeed have transistors and other sundry parts that enable them to generate high current low voltage outputs from 110, 115, 117, 220, 230, 240 etc volt AC input. I won't pretend that I can really explain how very well at all. But I do know that their design does allow for a variety of input voltages, I think even below 110, all the while providing "clean" regulated output to the rest of the machine. They are designed to be self regulating. Some do have a switch for 110 or 220 inputs (think of them as input ranges), and some will automagically just deal with it. The difference between 110, 115, 117, or like at my house about 122 is made up for by the self-regulating nature of the switching power supply design.

The reason that switching supplies are used exclusively is because of all the reasons above (inherently self regulating, etc), light weight, small size, and cheap. One common alternative is a linear power supply. I have a linear 5v 50 amp supply at the house that weighs 50+ lbs - because of big transformers, large caps, and a massive chassis to hold it all together. On the other hand, where the switching supply earns it's keep- I have a power supply for my Silicon Graphics Octane workstation that can probably supply 5v at 35 amps + (and +12 and -12v) all while weighing 10 lbs and being 1/8 the size.

I think the only reason that is ad says this is the "ultimate gamer supply" is because it's black (like putting Type R on the side of your ragged out, lowered Civic with the fat fake exhaust pipe) and because it's 550 watts. Some gaming rigs take bunches of juice, and purportedly this supply will crank it out without sagging, overheating, or complaining.

my 2 cent deposit-
mike

Let's play with their copy a bit. Switch the crazy long product name where it mentions "Switching" all the time with ferret:

If you want a ultimate gaming machine, the FERRET is your only selection for power supply. FERRET, as one of the top computer part manufacturer in the market, delivers 550W of power for your computer for as long as you want. FERRET include 550W power with dual 3 x 3-inch 820uf capacities silent fans, which keeps the power supply and computer case cool and quiet. FERRET add unique style to your computer case by painting the body of the FERRET with thick glossy painting. FERRET includes 4 Pin + 12V power connector for Pentium 4 CPU. Logisys ensure that each power supply it sold is in the highest quality possible by complies with FCC part 15J class B 115Vac Operation and CISPR22 230Vac Operation and meet UL 1950. CSA 22.2 Level 3 Requirement. Also FERRET provide maximum protection to end user by including over voltage protection, over power protection, and short circuit protection.

Now try to read about switching in there. It's not there. It's simply someone playing cut-n-paste with the ad copy so they get the repeated product "name."

A switching power supply means that it switches a (or a bank of) transistor on an off to regulate one voltage into another. The output can be higher or lower than the input voltage. In the good old days, power supplies used a transformer to lower the input voltage to something close to 2x the output voltage, rectified that into DC, and then used a linear regulator to get the final output. These supplies are about 65% efficient and also have a lot of power flowing through the supply that isn't used at all (low power factor).

That power supply doesn't have a voltage input switch because it's "power factor corrected". PFC supplies use a boost switching transistor to boot the input voltage to a much higher DC voltage, usually 300-400V and then use high frequency switching transistors to regulate back down to whatever voltages you want. These power supplies can be 92% efficient (but usually are 80-85%) and use almost all the power that flows into them (power factor usually .98 or .99) Nearly all modern PC power supplies are PFC. Frankly, I wouldn't buy one that wasn't.

Oh, one more thing. PC power supplies generally run most efficiently at 80% load. Don't just buy the biggest supply you can afford thinking it'll last longer or run cooler. Try to buy a supply that you will run between 50% and 80% load for the best efficiency.

OK so it's not PFC and I'm going blind. DON'T BUY IT.

OK so it's not PFC and I'm going blind. DON'T BUY IT.

How great a power supply could it possibly be for $17? ;^b

Betchya a nickel its fans (with plastic sleeve bearings, of course) say "BALL BEARING" in big letters on the hub.

--Peace