A power cord is a wire that transmits current. The usual method of current transmission is point-to-point transmission. Power cords can be divided into AC AC power cords and DC DC power cords according to their purpose. Usually, AC power cords are made of wire with higher voltage AC power. Due to the higher voltage, these types of wires require a unified standard to obtain safety certification before they can be officially produced. The DC line basically passes through lower voltage direct current, so the safety requirements are not as strict as AC lines. However, for safety reasons, countries still require unified safety certification.