The power adapter is also called external power supply. It is a power supply voltage conversion device for small portable electronic devices and electronic appliances. It is commonly used in mobile phones, LCD monitors and notebook computers, telephone handsets, game consoles, language repeaters, walkmans, cellular phones, etc. On electronic products.
Its role is to convert the 220 volt high voltage in the home into a stable low voltage of 5 volts to 20 volts that these electronic products can work, so that they can work normally.
Generally there are European regulations, US regulations, British regulations, Australian regulations and international standards.
The first is the British standard: AC plug - UK
The second is Australian Standard: AC Plug - AU
The third is the US standard: AC plug - US
The fourth is the European standard: AC plug - EU