As we know, the micro USB of Samsung Galaxy is different from our normal micro USB connector.This time, Green Connection MHL Adaptor for Galaxy S3 is coming....
The MHL adaptor is connected to the MicroUSB connector on the base of the Samsung Galaxy S3 to create a full size HDMI port. This can be used to attach an HDMI cable (not included) and allow a connection to an HDMI equipped screen.
The MHL HDTV adaptor has a microUSB port included in the design to accept power from a separate source such as the standard Galaxy S3 mains charger. This means that with the MHL adaptor you could watch a film stored on the Galaxy S3 on your HDTV and keep the phone charged at the same time.
Please note: For the MHL adaptor working you need to have it connected to main power.