Abstract: A power adapter apparatus comprises an AC power input adapted to receive AC power, an AC-to-DC converter, a switch, a timer, and a casing at least partially enclosing the AC-to-DC converter, the switch and the timer. The AC-to-DC converter is configured to convert the AC power to DC power. The switch is operable to connect the AC power input with the AC-to-DC converter, and to disconnect the AC power input from the AC-to-DC converter. The timer is operable to preset a desirable time at which the switch turns off to disconnect the AC power input from the AC-to-DC converter.