Power-saving method and electrical device using the same

A power-saving method for an electronic device having a display, comprising:

• detecting an orientation of the electronic device through a three-dimensional accelerometer;
• and
• activating a power-saving mode and adjusting the power consumption of the display based on the detected orientation.

A system for a mobile device, comprising:

• a detection unit configured to detect the position of the mobile device and configured to set a plurality of pre-determined positions of the mobile device as power-saving points;
• and
• an operational mode control unit coupled in signal communication with the detection unit, the control unit configured to receive signals representing the detected position from the detection unit and to control the mobile device to enter one of a power-saving mode and a wake-up mode based on the received signals.