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My brand new pair of bluetooth headphones stopped working after charging them with a 2.1 Amps USB outlet. I can't turn it ON anymore. I do see the LED battery Green then I charge it though. I noticed on the datasheet that the Amps for the headphones are 500mA and I've been charging them with my 2.1A usb plug. Could that have friend the circuitry? I'm not sure how battery works, for from Ohms law, IR=V if V is constant 5V, and R I'm guessing is too, then A could not vary.

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marked as duplicate by brhans, winny, Community Aug 13 '18 at 15:08

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  • \$\begingroup\$ Ohm's law doesn't really apply here as the load on the USB is not a resistor but a (charging) circuit. That circuit will take as much current as it needs (up to 500 mA as per datasheet). The USB port can deliver 2.1 A but it will only deliver as much current as the load takes, which is less than 0.5 A in your case. \$\endgroup\$ – Bimpelrekkie Aug 13 '18 at 14:38
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No, that's not the way it works. The USB supplies 5V at whatever current the device wants to draw, up to some maximum (2.1A in this case).

It is possible, however, for the USB outlet to be faulty and providing more than 5V, which could damage something plugged into it. Or the headphones could just have failed (infantile failures are not unknown in electronics).

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