Finally, your laptop can charge your tablet
Posted 11 January 2013 - 04:04 PM
And for what it's worth, in my experience any Mac's USB ports deliver enough power to charge any iOS device as long as the Mac is ON and not off or asleep.
Posted 12 January 2013 - 05:30 AM
Posted 13 January 2013 - 01:56 AM
No, this can't be the case. USB port must supply a constant 5V voltage - otherwise, it would fry the devices. You aren't providing trickle-charge voltage through USB port. The device receives a fixed voltage, which is then used to operate the charging circuit within.
The port nominally outputs up to 500mA of current, as per original USB specs, but iPhone can support 750mA and iPad, 2000mA. The wall chargers supplied with each of those products provide that much current.
In other words, this ChargrDr thing has to somehow manage to boost the current without dropping the voltage. It would have to somehow make the computer's mainboard to provide more current than it was originally designed to handle.
Posted 13 January 2013 - 01:37 PM
Posted 13 January 2013 - 01:39 PM
Oops...sorry for the double post...
Wesley...Ohm's Law... V=IR ....can't boost current without dropping voltage...they are inversely proportional...not sure how this thing works, but I'd be afraid of it's effects...slow charge with iPad off, or use it's charger/cable...