Quote:
Originally Posted by burnafterreading
incorrect as far as your claim that ALL devices not using a battery when plugged in.
my Galaxy Nexus has a removable battery (a Li-ion), and when plugged in with a microUSB cord, it'll charge the battery. while running, removing the battery causes the phone to completely shut off, and the power flowing from the USB charging port will not keep it turned on. and this is just a smartphone, not a power-hungry tablet. this is dead-easy to actually check on a case-by-case basis on any device in which you can remove the battery while using the device.
there's (at least) 2 ways of designing a device to run on AC-plus-DC
1 - AC charges battery only. battery feeds power to device. separate circuits.
2 - AC feeds power to device and charging circuit. when AC is gone, internal circuit switches to draw power from battery.
#1 is how most portable devices behave. there's NO interruption of power as long as the battery is connected (and in many cases, the battery is not easily replaceable anyways, so it's a safe bet)
#2 is how most affordable UPS / power backup systems work. the connected devices (pc, tv, etc) are usually able to handle a short blip in power (like one missing cycle from the 60Hz line frequency)
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Smart phones are still power hungry (just less
), which is why they usually ship with a power adapter with an output GREATER than 500mA (the Max permitted on a standard USB port).
Removing the battery just proves that the current limiter is working properly on your computer (or the internal sense circuit detects a real USB port and throttles the power to prevent USB port shut down).
Try your test with a 1A+ charger,