I've got several devices with a mini-B USB receptacle - including my mobile phone/PDA and some headsets. Each came with its own AC adapter. I'm wondering if I can charge any of these devices from any charger with a mini-B USB plug - (1) AC adapter (2) car charger (3) computer USB port with A-to-mini-B cable.

With wall warts I know you've got to match voltage, polarity, DC plug, and the charger must supply enough amps to power the device. But if the charger has a mini-B USB plug, does that take car of the voltage (+5V) and polarity?


Yes it does, in terms of polarity and voltage, but not current. Some chargers short pin 5 (iirc) in order to tell the device that "hey we're breaking the USB standard here and you can draw more current."

Motorola phones will happily send 750 mA down the line, Blackberries 800 mA (that may be reversed). Usually extra current is just extra capacity and you're fine--it won't hurt a device. Under-current, however, will most likely fail to charge. Poorly designed devices may malfunction.

The USB 2.0 standard is for a device to draw 100 mA--and then ask for more current; most devices don't follow that part of the standard. (I have a device that does...and it has a mode that says "draw 500mA no matter what")

USB 3.0 will increase the currents allowed to 900 mA, and allow 150mA inital draw.

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  • In addition: you can short the data pins (2 & 3) to indicate you're a charger and then the device can draw 500mA without issue. – Broam Jun 14 '11 at 20:16

I have had a problem with our GPS. It and my blackberry have a mini-usb connection, yet the GPS does not work on that charger. I would have said no for sure before I saw this with my own eyes, as I would think the very nature of USB would require the same size to work the same way.

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I think if it's the mini USB plug it's a standard connector and can be used on any device.

So far my HTC Hero hasn't had any trouble with the wires I got for other devices.

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Check the Voltage/amperage:

  • If they match then there shouldn't be any reason why it wouldn't.
  • If they don't match, I wouldn't bet my equipment on it.
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