Electrical connectors can be classified according to their uses, structures, interface types and other standards. The following are some common classifications of electrical connectors:

1. According to the purpose:
Power connector: used to transmit power signals, such as DC plugs and sockets.
Data connector: used to transmit data signals, such as USB, HDMI and RJ45.
Signal connector: used to transmit control signals or sensor signals, such as D-sub connector and XLR connector.

2. According to the structure:
Round connector: the connector is round in shape and is commonly used in aerospace field.
Rectangular connector: the connector is rectangular in shape and is commonly used in industrial equipment and electronic equipment.
PCB connector: a connector installed on a PCB, which is used for the connection between circuit boards.

3. According to the interface type:
USB connector: used for connection between computer and peripheral equipment.
HDMI connector: for high-definition multimedia interface.
XLR connector: used for connecting audio equipment.
RJ45 connector: used for network connection.

4. According to the connection mode:
Plug-in connector: it needs to be inserted or pulled out manually.
Magnetic connector: automatic magnetic connection.
Crimp connector: Connect wires by crimping.

5. According to the protection level:
Waterproof connector: it has waterproof function and is often used in outdoor equipment or wet environment.
Dustproof connector: It has dustproof function and is often used in industrial environment or dusty places.

The following factors can be considered when selecting an electrical connector:

Current and voltage requirements: determine the maximum current and voltage that you need the connector to withstand. According to your circuit requirements, choose the appropriate connector to ensure that it can safely transmit the required current and voltage.

Interface Type: Select the connector according to the interface type of the equipment or component you want to connect. Common interface types include USB, HDMI, RJ45 (network cable), XLR (audio), DC plug and so on. Make sure that the connector matches the interface of the device you want to connect.

Durability and quality: choose durable and reliable connectors to ensure long-term and stable connection. High-quality connectors are usually made of high-quality materials and can withstand frequent plugging and use.

Protection function: If connection environment has some special requirements, such as waterproof, dustproof, seismic, etc., you can choose a connector with corresponding protection function to protect the circuit from the external environment.

Accessibility and compatibility: Check the accessibility and compatibility of the selected connector. Make sure it is compatible with the equipment or components you want to connect, and you can easily get the required accessories and replacement parts.

Safety: choose connectors with safety features, such as anti-reverse insertion function and anti-misoperation design, to ensure safety in use.