2 Replies Latest reply: Mar 14, 2014 7:32 AM by SeanCota
Kelly Crossley Level 3 Level 3
expertise.macosx
Mac OS X

I've see USB hubs with voltages like 5v, 12v, and 24v being made.

 

  1. How much power are the USB 2/3 ports on the Mid-2012 MacBook Pro capable of?
  2. Does USB 3 delover more power than USB 2?
  3. How does a USB device regulate the power it gets from the MacBook Pro's USB ports? In other words, what happens if the port is generating 12v of power, but the device only needs 5v?
  • clintonfrombirmingham Level 7 Level 7
    expertise.macosx
    Mac OS X

    See http://support.apple.com/kb/HT4049 - USB 3.0 ports on the 2012 models are 5v. USB 2.0 ports on previous machines are 5V as well.

     

    CLinton

  • SeanCota Level 1 Level 1

    USB ports are all 5 Volts DC.  Depending on the device, the Amperage (how much power flows) is important.  My experience is that iPads need a minimum of .8 Amps DC {800 mA (milliamps)}

     

     

    From Apple:

    USB 1.1 or USB 2 ports:

    Up to 500 mA (Milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.

    Apple computers with USB 3 ports provide:

    USB 3 ports:

    Up to 900 mA (milliamps) at 5 V (Volts) to most Apple USB peripherals and all USB peripherals not made by Apple in compliance with USB specifications.