Loads of devices these days have USB links to enable you to link them to the PC - eBooks, MP3 players, tablets and so on. To save cable the same USB cable also has a link to a plug that goes straight to the mains via a USB converter.

Since all use a USB link, can I use the same plug to charge all devices since each will fit the USB plug or will a Samsung plug only charge a Samsung, a Kindle plug only charge a Kindle, etc.?


closed as off-topic by Leon Heller, Stephen Collings, Kaz, Joe Hass, Daniel Grillo Dec 30 '13 at 18:14

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Most such devices will be fully compatible with a standard USB cable fed with standard USB power. However, some devices (notably the iPad) have much higher power requirements and will only operate (i.e. not charge) when plugged into a non-compatible charger or PC USB port. This is to prevent the power source from being over-drawn (the iPad draws about 1 amp @5v to charge, for example). The standard USB power level is much lower (under 0.5 amp typically).

These high charging power devices recognize compatible chargers by the presence of a resistor bridge on the D+/D- lines, so it is possible to build your own (high) power charger that will trick your device into accepting the charge.

  • \$\begingroup\$ Thanks Ron. I'm not an electricity wizard though so the simple question remains - will one charger charge the whole lot (excluding any iPads) please - one at a time obviously? \$\endgroup\$ – HugMyster Dec 30 '13 at 15:36

Barring some manufacturer misusing USB-like connectors in non-standard ways, then yes, you can use any USB charger to charge any USB-compatible rechargable device.

Having said that, Apple uses the data lines in their USB chargers in an unusual (but compatible) way to tell i-devices how much current the charger can supply; they in turn, limit their current draw accordingly. (LadyAda of adafruit Industries reverse engineered the protocol if you're interested in the gory details). If your charger doesn't use the Apple technique your iOS device will just charge slower than it might otherwise be able to. Other devices will draw what they can. There are third party chargers that have both Apple-compatible and non-Apple charging ports. I have used one such with a Kindle Fire, an iPod touch, and a Nexus 7, and all of the gadgets are still happy.

  • \$\begingroup\$ I don't have enough reputation to mark this one I'm afraid but that's VERY useful - thanks! Would you happen to know if a Samsung charger would work charging a Kindle please? The Kindle does not provide a charger, only the USB cable. \$\endgroup\$ – HugMyster Dec 31 '13 at 8:43
  • \$\begingroup\$ I don't know the particular charger but as long as it and its phone use a standard USB cable, then the Kindle should like it as well. Then the only question would be how fast it will charge the Kindle. The charger should be labeled with either its output current or wattage. A 10 watt or 2 amp charge is probably ideal. More is no problem (but also unlikely); less will just charge slower. \$\endgroup\$ – JRobert Jan 2 '14 at 22:08

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