What Factors Will Affect the Reliability of Pin Contact Resistance of RJ45 Connector

1、 Vertical pressure

Vertical pressure refers to the force generated by the surfaces in contact with each other and perpendicular to the surface of the contact. With the increase of vertical pressure, the number and area of contact micro points increase gradually, and the contact micro points transition from elastic deformation to plastic deformation. Because the concentrated resistance decreases gradually, and the contact resistance decreases, the vertical pressure of the contact mainly depends on the geometry and material properties of the contact.

2、 Contact material

Because the technical conditions of electrical connectors stipulate different contact resistance assessment indexes for contacts of the same specification made of different materials. General specification for quick release environment resistant electrical connector gjb101-86 stipulates that the contact resistance of plug-in contact with a diameter of 1mm is ferroalloy ≤ 15m Ω and copper alloy ≤ 5m Ω.

3、 Service voltage

Service voltage means that when a certain threshold is reached, the contact film will be broken down and the contact resistance will drop rapidly. However, the thermal effect accelerates the chemical reaction near the film and has a certain repair effect on the film. Therefore, the resistance value is nonlinear. Near the threshold voltage, the small fluctuation of voltage drop will cause the current to change in the range of 20 times or dozens of times.

4、 Surface morphology

Surface morphology mainly refers to the shape of the design and the environmental state.

Design shape: due to the pollution film formed by physical adsorption and chemical adsorption, it is mainly chemical adsorption on the metal surface, which is produced with electron migration after physical adsorption. Therefore, some products with high reliability requirements, such as aerospace electrical connectors, must have clean assembly and production environmental conditions, perfect cleaning process and necessary structural sealing measures, and the user must have good storage and operation environmental conditions.

Environmental state: some contact surfaces may have loose surface films formed by mechanical adhesion and deposition on the contact surface due to dust, rosin, oil stain, etc. this surface film is easy to be embedded in the micro pits of the contact surface due to particulate matter, which reduces the contact area, increases the contact resistance and is extremely unstable.