Today I try to charge my iPad 3 over a power splitter I bought on big c

Was not a good ida the light come out and power cord splitter was gone god bless iPad still alive

I can charge the iPhone 4 over notebook and computer USB,but iPad 3 cannot how much more power iPad 3 takes then the iPhone?

Sent from my iPhone using ThaiVisa app

iPads from (I think) the iPad 2 onwards can't be charged from the USB port of a computer. The power isn't sufficient or it's related to Apple being a bunch of Nazis or something.

You can charge an iPad on a "high power" usb port:

To charge your iPad battery, try one of the following:

• Connect iPad to a power outlet using the included cable and USB power adapter (use the table below to determine which adapter is intended for your iPad.)
  
• Connect to a high-power USB 2.0 port using the included cable.
  

Note: Some USB 2.0 ports and accessories do not provide enough power to charge iPad. When this occurs the message "Not Charging" appears in the status bar next to the battery icon.

From: http://support.apple.com/kb/HT4060

Not all USB ports are high power output. It's possible you may be able to slowly recharge an iPad on a low power USB port if the screen is off. The iPad screen is much bigger than the iPhone, so it takes more power to run.