1. Pins and spacing
The number of pins and pin spacing are the basic basis for connector selection. The number of pins chosen for the connector depends on the number of signals that need to be connected. For some chip connectors, the number of pins should not be too many. Because in the welding process of the placement machine, due to the high temperature, the plastic of the connector will be deformed by heat, and the middle part will bulge, resulting in virtual welding of the pins.
2. Electrical performance
The electrical properties of the connector mainly include: limiting current, contact resistance, insulation resistance and electric strength. When connecting a high-power power supply, pay attention to the limiting current of the connector; when transmitting high-frequency signals such as LVDS, PCIe, etc., pay attention to the contact resistance. Connectors should have low and constant contact resistance, typically tens of mΩ to hundreds of mΩ.
3. Environmental performance
The environmental performance of the connector mainly includes: temperature resistance, humidity resistance, salt spray resistance, vibration, shock, etc. Choose according to the specific application environment. If the application environment is relatively humid, the requirements for the connector’s moisture resistance and salt spray resistance are high, so as to prevent the metal contacts of the connector from being corroded. In the field of industrial control, the requirements for the anti-vibration and shock performance of the connector are high, so as to prevent the connector from falling off during the vibration process.
4. Mechanical properties
The mechanical properties of the connector include plugging force, mechanical foolproofness, etc. Mechanical foolproofing is very important for connectors. Once inserted backwards, it is likely to cause irreversible damage to the circuit!
Insertion force is divided into insertion force and separation force. The relevant standards stipulate the maximum insertion force and the minimum separation force. From the perspective of use, the insertion force should be small and the separation force should be large. If the separation force is too small, the reliability of the contact will be reduced. However, for the connector that needs to be plugged and unplugged frequently, if the separation force is too large, it will increase the difficulty of pulling out and reduce the mechanical life.