According to function, it can be divided into:
Headphone plug, DC plug, audio plug, USB plug, video plug, microphone plug, charger plug, mobile phone plug, etc. Internationally, household appliances are divided into three categories:

Class A: Electrical appliances are only one layer of insulation measures of electrical appliances, this kind of electrical appliances must be added leakage protection, and ground protection (that is, to three-pin plug). Such as air conditioning, machine tools, motor and so on.

Class two: electrical appliances have double insulation measures, to add leakage protector, you can not ground protection (that is, you can use a two-pin plug). Such as TV, electric fan, table lamp, induction cooker, electric clay oven and so on.
Category Three: Electrical appliances are appliances that use safe voltage, generally 12-36V electrical appliances, such as mobile phones, laptops, etc.

According to the safety certification classification:

UL/CUL, VDE, CCC, T-MARK, SAA, BSI, PSB, SABS, PSE, SNI, UC, etc