Efficiency of Computer Power Supplies

[tashirosgt]

How efficient are the "switching" power supplies that are commonly used in computers? For example, would someone building a "energy saving" device that needed to draw 12V and a few amps from the main power, use such a supply? Or do they have an even more efficient way of doing it?

[rerushg]

Switching power supplies are not terribly efficient. For a few amps @ 12 volts a simple transformer probably makes more sense. In other words, you could use an "AC adapter" (the "power brick") for laptops, game consoles, cell phones, etc. You mght even find aan old one laying around the house or garage that will do fine. If not, check Ebay for AC adapters. It doesn't matter what device the adapter is intended for. As long as it outputs the voltage you want and at least the current you need you're good to go. Probably cost $15-20US + shipping.

[w5set]

Actually a switching power supply is ....(then old style transformer power supplies for computers)
1. Less weight.
2. Less cost.
3 Way more efficient.
4. Less wasted heat generated.

Actually even cheap switchers are in the 85% + efficiency range--better ones usually hit 92% or better. A range only the very best transformer types could hit with careful design and a narrow range of amps output at the best with attendant high costs too.