Apple - Can I use my iPhone charger for charging other USB based devices?
Most standard USB charges for 0.5A. But not all USB are standardized - there are some that go for up to 1.8A and even the MacBook Pro is said to raise up to 1.1A when relevant. iPhone's charger do little more than 1.1A and it's pretty decent. That's why iPhone charging on regular USB usually take double the time to fully charge. iPad's charger are roughly 10W and 5V which translates to 2A.
There's nothing wrong that can happen with the charger because USB devices are made to work with the same standard voltage (about 5V). The USB hosts are only outputting the maximum energy it can provide up to what the client can receive. A 10W energy source will only give up to 10W and just 1W if the plugged device can only take 1W.
I'm no electrical specialist but...
Having bigger power supply (measured in watts) or bigger current (measured in amperes) on itself can't break any system because what puts them in movement is the difference of potential measured by volts.
Think of a light bulb and picture all USB devices are prepared to receive about 5V (actually little more). If you get a 220V and put in on a 110V nothing wrong happens, but it will be very weak. Apple's chargers only go up to 5V, which is within the USB standard. So yeah, it's all good and safe.
Yes, you can. It converts the AC power to the standard USB power, so anything that charges with USB will charge with the iPhone's adapter.
Regarding to USB charging, there are two kinds of USB devices:
- Dumb ones that doesn't check if they are connected to a charger and always use less than 100 milliamperes. Some use up to 500mA, but they are out of USB specs.
- Smart ones that check if they are connected to a charger and try to use full power of the charger (up to 1800mA or 2100mA).
Apple USB chargers (1000mA to 2100mA) are of the second type but doesn't follow the USB charging standard (1800mA) and aren't compatible with other smart devices that follow that standard. Only with dumb devices and other apple devices.