Classification of plugs

Divided by function:
Headphone plugs, DC plugs, audio plugs, USB plugs, video plugs, microphone plugs, charger plugs, mobile phone plugs, etc. Internationally, household appliances are divided into three categories:
Category 1: Appliances that have only one layer of insulation. These appliances must have a leakage protector and grounding protection (which means they need a three-prong plug). Examples include air conditioners, machine tools, motors, etc.
Category 2: Appliances with double insulation measures. They need a leakage protector but do not require grounding protection (which means they can use a two-prong plug). Examples include televisions, electric fans, table lamps, etc.
Category 3: Appliances that use safe voltage, generally 12-36V appliances.
Therefore, one prong of the three-prong plug is used for grounding protection.
Classified by safety certification:
UL/CUL, VDE, CCC, T-MARK, SAA, BSI, PSB, SABS, PSE, SNI, UC, etc.
Abbreviations for plug certifications in various countries
China: CCC
USA: UL/CUL
Canada: CSA
UK: BS
Netherlands: KEMA
Belgium: CEBEC
Switzerland: SEV
Germany: VDE
France: NF
Italy: IMQ
Norway: N
Denmark: DEMKO
Finland: FI
South Africa: SABS
Sweden: S
Japan: PSE
South Korea: KTL
Australia: SAA
New Zealand: SANZ
Argentina: IRAM
Brazil: INMETRO
Divided by structure:
Divided into plugs, sockets, and connectors. Plugs and sockets are generally divided into two-prong and two-prong with grounding.
Many modern appliances still have current flowing through them even when not in use, as long as the plug is inserted. Therefore, it is advised that any appliance not in use should have its plug removed to save electricity.
For power products, there are usually four terms: 1. Plug. Refers to the part that connects to the power cord and has a male prong; the full name should be plug connector. 2. Connector. Refers to the part that connects to the power cord and has a female socket; the full name should be connector. 3. Appliance inlet. Similar to 1, but installed on fixed bodies like appliances and not connected, including those installed on the socket body. 4. Socket. Similar to 2, but with the same installation position as 3; the full name should be appliance socket.
We often confuse terms 2 and 3, usually calling those with prongs plugs and those with holes sockets, but they are actually different.