How To Choose A Connector Suitable For Hardware Application?

How to choose a connector suitable for hardware application?

The connector is like the function interface of the program. If the design is reasonable, future product maintenance, upgrades, and transplantation will get twice the result with half the effort, so that the product can maintain long-lasting vitality; the unreasonable design will cause difficulties in future maintenance and upgrades, which will affect the whole body. Z eventually makes the product lose competitiveness, and the importance of the connector is self-evident.

Connectors, which are commonly called connectors by engineers, are used to connect two circuit boards or electronic devices to achieve power or signal transmission. Through the connector, the circuit can be modularized, the assembly process of the electronic product can be simplified, and the product can be easily maintained and upgraded.

For modular circuits, the selection of connectors plays a pivotal role. So when choosing connectors, from which angles should we consider connectors suitable for hardware use?

1. Pins and spacing

The number of pins and the spacing between pins are the basic basis for connector selection. The number of pins to choose a connector depends on the number of signals that need to be connected. For some patch connectors, the number of pins in the patch headers as shown in the figure below should not be too much. Because in the soldering process of the placement machine, due to high temperature, the connector plastic will be heated and deformed, and the middle part will bulge, resulting in false soldering of the pins. Our P800Flash programmer used this kind of header and female header to connect between boards in the early stage of development. As a result, the pins of the prototype header were soldered in a large area. After changing to 2 pin headers with halved pins, there was no false soldering.

Nowadays, electronic equipment is developing towards miniaturization and precision, and the pin pitch of the connector has also changed from 2.54mm to 1.27mm and then to 0.5mm. The smaller the lead pitch, the higher the requirements for the production process. The lead spacing should be determined by the company's production technology level. The blind pursuit of small spacing will cause difficulties in production and maintenance.

2. Electrical performance

The electrical performance of the connector mainly includes: limit current, contact resistance, insulation resistance and dielectric strength, etc. When connecting a high-power power supply, pay attention to the limit current of the connector; when transmitting high-frequency signals such as LVDS, PCIe, etc., pay attention to the contact resistance. The connector should have a low and constant contact resistance, generally tens of mΩ to hundreds of mΩ.

3. Environmental performance

The environmental performance of the connector mainly includes: resistance to temperature, humidity, salt spray, vibration, shock, etc. Choose according to the specific application environment. If the application environment is relatively humid, the requirements for resistance to humidity and salt spray of the connector are high 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 insertion force, mechanical foolproofness, etc. Mechanical foolproof is very important to the connector. Once plugged in reverse, it may cause irreversible damage to the circuit!

The insertion force is divided into insertion force and separation force. The relevant standards stipulate Z large insertion force and Z small separation force. From the perspective of use, the insertion force should be small and the separation force should be large. Too little separation force will reduce the reliability of contact, but for connectors that often need to be plugged and unplugged, too much separation force will increase the difficulty of unplugging and reduce the mechanical life.