A power adapter is a small portable electronic device that typically consists of a casing, transformer, rectifier circuit, filter circuit, voltage regulator circuit, and other components. Its design aims to ensure the safe and stable operation of electronic devices. Power adapters are widely used in various portable electronic devices, including but not limited to laptops, tablets, smartphones, digital cameras, game consoles, etc. These devices typically use built-in batteries for power supply, but the battery life is limited, so they need to be charged or powered through a power adapter connected to the grid.