The engineers of Shengrui technology tell you how to choose the connector

 The engineers of Shengrui technology tell you how to choose the connector

Editor: Shengrui Technology Center

The engineers of Shengrui technology tell you how to choose the connector? There are many kinds of connectors, including communication interface terminal, wiring terminal, line to board connector, board to board connector, etc. Each category can be subdivided into several categories, such as: board to board connector, including pin row bus, board to board connector, etc; The cable-to-board connector includes FPC connector, IDC socket, simple bracket, etc.

So what should we consider when choosing connectors for hardware use?

1. Pin, spacing

The number of pins and the spacing of pins are the basic basis for connector selection. The number of pins selected depends on the number of signals to be connected. For some patch connectors, as shown in the figure below, the number of pins should not be too many. Because in the process of welding, due to high temperature, the connector plastic will be deformed by heating and the middle part is raised, resulting in the pin false welding. Our p800flash programmer used this kind of pin and bus as the connection between plates in the early stage of research and development, and the pin of the sample pin was welded in large area. After replacing the two pin number by half, no false welding has occurred.

Nowadays, electronic equipment is becoming smaller and more precise. The pin spacing of connectors also ranges from 2.54mm to 1.27mm to 0.5mm. The smaller the pin spacing, the higher the requirements for production process. The pin spacing should be determined by the company‘s production process level, and blind pursuit of small spacing

2. Electrical performance

The electrical performance of the connector mainly includes: limit current, contact resistance, insulation resistance and resistance strength. When connecting high power supply, pay attention to the limit current of connector; When transmitting high frequency signals such as LVDS, PCIe and other signals, pay attention to contact resistance. Connectors shall have low and constant contact resistance, generally tens of meters Ω To hundreds of meters Ω。 3. Environmental performance

The environmental performance of connector mainly includes: temperature resistance, humidity resistance, salt fog resistance, vibration, impact, etc. According to the specific application environment selection. If the application environment is humid, the requirements for the connector are high for the resistance to humidity and salt spray, so as to avoid corrosion of the metal contacts of the connector. In the field of industrial control, the requirements for the anti vibration and impact performance of connectors are high, so as to avoid the connector falling off during vibration.

4. Mechanical properties

Mechanical properties of the connector include pulling force, mechanical anti stay, etc. Mechanical anti stay is very important to the connector. Once the plug is reversed, it is likely to cause irreversible damage to the circuit!

The pulling force is divided into insertion force and separation force. The maximum insertion force and the minimum separation force are specified in the relevant standards. From the perspective of use, the insertion force is small and the separation force is large. Too small separation force will reduce the reliability of contact. However, for connectors that need to be plugged and plugged frequently, excessive separation force will increase the difficulty of pulling out and reduce the mechanical life.

In order to reduce the separation force of connectors and facilitate users to plug and plug the adapter board, we made many attempts. Finally, we found a bright light on the road to explore, finally selected the connector shown in the figure below, and modified the PCB and product shell structure.

The actual test shows that the connector has the advantages of unique direction, obvious anti stay effect, small insertion force, moderate separation force, good sense of plug and plug, which greatly improves the convenience of plug-in.

Connector, which is commonly known as the engineer, is used to connect two circuit boards or electronic devices to realize the transmission of power or signal. Through the connector, the circuit can be modularized, the assembly process of electronic products can be simplified, and the products can be easily maintained and upgraded. For modular circuits, the selection of connectors plays an important role.