USB 3 Info Please

[jparker402]

Have an early 2015 MacBook Air which has two USB 3 ports. Have a WD My Passport external drive plugged into one of them. Just finally after about four years of not really thinking about realized that the external drive is not only receiving data through that port, but is also being powered through that port! Got the WD drive when I got the computer, just plugged it in and it worked. So I was happy and never thought anything about it. And, following the 2020 MacBook Air and Thunderbolt 3 info, now discovered that there are powered dongles, adapters and things to provide power to the accessories. Since my 2015 MBA is now powering my WD drive, what else could this computer power through its USB 3 port? Is there some kind of voltage limit? Tell why I might need a powered adapter now or in the future. Thanks!

 

[barbu]

You’d need a power adapter for any device that draws more than USB can provide. I don’t know the specs offhand, but something a full size spinning hard drive tends to require additional power.

 

[jparker402]

Thank you! Got me to thinking how one could find out. Went here: https://support.apple.com/en-us/HT204377, and it showed me how to find out how much power it was drawing. And, since the MBA hasn't given me that screen that says I am asking for too much power, guess that let's me know what it needs. Didn't you one could find out how much power was being drawn! Thanks again!