14 basic principles for connector selection

There are a wide range of commonly used connectors, and the selection methods for different types of connectors are different. Although there are many types, its selection needs to follow the following 14 points, which mainly include fourteen criteria such as carrying capacity, impedance matching, shielding, versatility, cost, and availability.

1. Carrying capacity When selecting a power signal connector, you should pay more attention to the carrying capacity of the connector. You should adopt a derating design and pay attention to the insulation withstand voltage between the pins.

2. Structural dimensions: The external dimensions of the connector are very important. There are certain space restrictions for connections in the product, especially the connectors on the single board, which cannot interfere with other components. Select the appropriate installation method (front installation and rear installation, installation and fixation methods include rivets, screws, clamp rings or bayonet quick locking of the connector itself, etc.) and appearance (straight, curved, T type, round, square).

3. Impedance matching

Some signals have impedance requirements, especially radio frequency signals, which have stricter impedance matching requirements. Mismatched impedance will cause signal reflection, thus affecting signal transmission. General signal transmission has no special requirements for the impedance of the connector.

4. Shield

With the development of communication products, EMC is receiving more and more attention. The selected connector needs to have a metal shell. At the same time, the cable needs to have a shielding layer. The shielding layer must be connected to the metal shell of the connector to achieve a shielding effect. It can also The injection molding method is used to wrap the plug part with copper, and the shielding layer of the cable is welded to the copper.

5. Prevent misinsertion

There are two aspects to preventing mis-insertion: On the one hand, the connector itself is rotated 180 degrees and misaligned, resulting in incorrect signal connection. At this time, you need to pay attention to choosing a connector that prevents mis-insertion as much as possible, or by adjusting the relative position of the connector. Make the assembly unique; on the other hand, in order to reduce the type of materials, several signals use the same connector. At this time, plug A may be inserted into plug B. At this time, you need to pay attention. If this happens, If serious consequences occur, the A and B interfaces must be selected as different types of sockets.

6. Reliability Connectors are used to connect signals, so the connection parts must be reliable (for example, surface contact is better than point contact, pinhole type is better than leaf spring type, etc.). 7. Versatility In the selection process of connectors, universal objects should be selected as much as possible, especially between products of the same series. The selection of connectors has strong versatility, reducing the types of materials, increasing quantity and cost, and at the same time reducing supply. risk. 8. Use environment When connectors are used outdoors, indoors, in high temperature, high humidity, salt spray, mold, cold and other environments, there are special requirements for the connector.

9. Lock function

In order to prevent the connector from falling off when mated and ensure good contact, the connector needs to have a locking function.

10. Cost

Cost is also an important factor in the selection process. As market competition becomes increasingly fierce, appropriate selection of connectors, the connector's own cost and processing costs need to be comprehensively considered.

11. Availability

The supply of connectors will be affected by many factors. Universal connectors have better supply than non-universal connectors, and domestically produced connectors have better supply than foreign ones.

12. Plug and unplug frequency

The plugging and unplugging of connectors have a certain life span. After the number of plugging and unplugging reaches the limit, the performance of the connector will decrease. When some signal interfaces require frequent plugging and unplugging, you should pay more attention to the number of plugging and unplugging of the connector when selecting a connector.

13. Considering whether it is charged or not, choose a pin-type or hole-type connector.

14. Comprehensive consideration In the process of selecting a connector, various factors are not independent and often interact with each other. Therefore, we must consider comprehensively in the connector selection process and choose the most appropriate connector. The quality of the choice lies in Different stages will affect the product to varying degrees