External hard disk

[don2]

What is power type external hard disk?

what is power less external hard disk?

please explain in detail !!!

[alaindc]

I will try.

A portable hardrive is USB powered, and don't need external power source (only usb).

You connect the Usb cord, and that's it.

you can use it anywhere.

this one is probably the power less HD you talk about.

An external hardrive...have a power adaptor you need to connect, plus the USB cord.

you plug the AC adaptor, then the usb cord, for it to work.

if you can't connect the AC adaptor, it won't work, at all.

[Whoopenstein]

The one I have uses a power supply similar what is used on a laptop. I would be concerned if the drive (desktop size) sucked that much current from just the USB.

[GRiM]

Generally it depends on size of drive. For example a 2.5" (laptop internal hdd) external can use the 5v USB power output. A 3.5" (desktop internal) external drive will need additional power source.

[Guinness]

Yep, 3,5´ E-Hdd´s need both 5V and 12V to operate, and generally requires about 20 Watts to startup, so a separate power brick is needed.

2,5´ E-Hdd´s requires only 5V, generally about 500mA (using one USB 2.0 port) or 1A (using two USB 2.0 ports) so you can use them via USB 2.0 5V Bus-Power.

Edited October 10, 2013 by Guinness