Abstract: A power adaptor including a USB connector, a DC power input port, a DC power output port and a DC/DC voltage regulator. The DC power output port is electrically connected to the DC power input port. The DC/DC voltage regulator is electrically connected to the USB connector and the DC power input port for lowering the voltage of the power input from the DC power input port and outputting the power to the USB connector. The power adaptor is adaptable to a notebook computer charger to charge another portable electronic product such as a mobile phone, a PDA or an iPod. The charging process can be performed without powering on the notebook computer so as to facilitate use and save energy.