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For computers' power supply:

  1. Are both power adapter and power supply unit used for converting main AC to DC?
  2. Is power adapter used for laptop but not for desktop, while power supply unit for desktop but not for laptop?

Or do they co-exist for a computer for different purposes?

Thanks!

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closed as not a real question by Shinrai, 8088, Dave M, Indrek, Diogo Aug 28 '12 at 20:30

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Can you be more specific about what you're looking to know? This makes very little sense to me out of context. –  Shinrai Aug 28 '12 at 19:43
    
Context: for computers' power supply. –  Tim Aug 28 '12 at 19:44
    
I guess I'm just confused because some people use the terms "power adapter" and "power supply" interchangeably, when talking about laptops. –  Shinrai Aug 28 '12 at 19:54

2 Answers 2

up vote 1 down vote accepted
  1. Yes.

  2. A laptop power adapter converts AC to a single DC voltage, which when supplied to the laptop is then broken down/up into the different voltages required by the laptop. The power supply unit in a desktop takes AC and converts into the different voltages required by the components within the case.

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Thanks! So power adapter is used for laptop but not for desktop, while power supply unit is for desktop but not for laptop? They don't co-exist, because that would be duplicate? –  Tim Aug 28 '12 at 19:49
    
@Tim there must be some other issue here, because I was quite clear that when I referred to the power source for a laptop, I called it a power adapter and when I referred to the power source for a desktop I called it a power supply unit. Thus, I fail to see the ambiguity that you need to be clarified. The unit for a laptop an an external AC/DC converter. The unit for a desktop is a larger metal box that converts AC to multiple different DC voltages. The two are similar (convert AC to DC) but otherwise very different and not interchangeable. –  Bon Gart Sep 2 '12 at 16:40

Computers do run off of DC power. There are power supplies that are DC input only, typically found in servers, not desktops.

There are desktop units that run off adapters. Obviously, they dont take huge power draws. What the definition of desktop is variable.

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Thanks! What differences are between power adapter and power supply unit? Are they for different purposes? Do they co-exist? –  Tim Aug 28 '12 at 19:48
    
@Tim Based on the answers here, I believe the adapter is the part that converts AC to DC, and the PSU is the part that regulates the voltages for the different parts of the computer. All require an adapter (by this definition) in some form factor or another, because consumer electricity is AC. All require a PSU in some form factor or another, to get the proper voltages to the different parts, be they laptop, desktop, server, etc. –  JoshP Aug 28 '12 at 20:11

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