Sandman
A PSU never has any power. A PSU has a power input and a power output. It never has any power of its own.

Eric Stevens
A Power Supply Unit never has any power.

Sandman
Correct.

Eric Stevens
You have switched terminology and are using it in a very particular context. The original discussion was over from where the iPhone obtained it's power. As can be seen above Whisky-dave said "A battery can be said to be suplying power to the device."

At this point you came in and said "Supplying power != Power supply."

It was at this point you switched to using 'Power Supply Unit' rather than 'Power Supply'.

Sandman
A battery is a power *SOURCE*, just as your wall socket is a power *SOURCE* (or rather, the power plant that produces the power). A PSU takes power from a power source and regulates it for the load. It does not - I repeat - it does not have any power on its own.

Eric Stevens
That's the Sandman definition.

Sandman
No, it's the actual definition.

<http://en.wikipedia.org/wiki/Power_supply>

Eric Stevens
I hadn't quite caught up with your jump and, in that context, you are quite correct. However, it is not what we had been discussing.

Sandman
"A power supply is an electronic device that supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters."

Will Eric argue for days more or just quietly ignore this thread?

Eric Stevens
I will argue with the terminology used in that paragraph

Sandman
"All power supplies have a power input, which receives energy from the energy source, and a power output that delivers energy to the load"

Whoa, would you look at that - that's pretty much verbatim what I just said.

Eric Stevens
And could apply just as well to a battery being charged from an external source.

Sandman
A PSU, or power supply, ...

Eric Stevens
Make up your mind. You are the one who wrote "Supplying power !>Power supply." A PSU can't supply power. All it can do is process the power with which it is supplied.