Patent ID: 7714568

Claim:
A power supply for receiving an AC voltage and outputting a DC voltage and an output current to an electronic device, the power supply comprising: an input module configured to receive the AC voltage; an output module configured to output the DC voltage and the output current to the electronic device; a measuring interface configured to electrically contact with a part of the electronic device; a measuring module configured to measure the DC voltage, the output current, and a voltage and a current of the part of the electronic device; and a switch module operable to choose one of the output module and the measuring interface to be electrically connected to the measuring module; the switch module comprising: a first relay comprising a double pole double throw switch and a coil, the double pole double throw switch operable to allow the measuring module to measure the DC voltage or the voltage of the part of the electronic device; a second relay operable to allow the measuring module to measure the output current or the current of the part of the electronic device; and a controller electrically connected to the first relay via a first resistor and electrically connected to the second relay via a second resistor, the coil of the first relay being controlled by the controller to change states of the double pole double throw switch.