The basic performance of connectors falls into three categories

The basic performance of connectors can be divided into three categories: mechanical performance, electrical performance and environmental performance.

1. Mechanical properties as far as the connection function is concerned, the plugging force is an important mechanical property. Insertion force is divided into insertion force and pull-out force (pull-out force is also called separation force), and their requirements are different. There are provisions on the maximum insertion force and minimum separation force in relevant standards, which shows that from the perspective of use, the insertion force is small (thus the structure with low insertion force LIF and no insertion force ZIF), and if the separation force is too small, it will affect the reliability of contact.

Another important mechanical property is the mechanical life of the connector. Mechanical life is actually an index of durability, which is called mechanical operation in the national standard gb5095. It takes one insertion and one pull-out as a cycle, and takes whether the connector can normally complete its connection function (such as contact resistance value) after the specified plug-in cycle as the evaluation basis.

The plugging force and mechanical life of the connector are related to the contact structure (positive pressure), the coating quality of the contact part (sliding friction coefficient) and the dimensional accuracy (alignment) of the contact arrangement.

2. Electrical properties the main electrical properties of the connector include contact resistance, insulation resistance and electrical strength.

① Electrical connectors with high contact resistance should have low and stable contact resistance. The contact resistance of the connector ranges from a few milliohms to tens of milliohms.

② Insulation resistance is an index to measure the insulation performance between contacts of electrical connectors and between contacts and shell. Its order of magnitude ranges from hundreds of megaohms to hundreds of gigaohms.

③ Electrical strength, or voltage resistance and dielectric withstand voltage, is the ability to withstand the rated test voltage between connector contacts or between contacts and housing.

④ Other electrical properties.

Electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector. Electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector. It is generally tested in the frequency range of 100MHz ~ 10GHz.

For RF coaxial connectors, there are also electrical indexes such as characteristic impedance, insertion loss, reflection coefficient, voltage standing wave ratio (VSWR). Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signals, a new type of connector, high-speed signal connector, has emerged. Accordingly, in terms of electrical performance, in addition to the characteristic impedance, there are also some new electrical indicators, such as crosstalk, transmission delay, skew and so on.

3. Environmental performance common environmental properties include temperature resistance, humidity resistance, salt spray resistance, vibration and impact resistance.

① At present, the maximum working temperature of the connector is 200 ℃ (except for a few high-temperature special connectors), and the minimum temperature is - 65 ℃. When the connector works, the current generates heat at the contact point, resulting in temperature rise. Therefore, it is generally considered that the working temperature should be equal to the sum of ambient temperature and contact temperature rise. In some specifications, the maximum allowable temperature rise of the connector under the rated working current is clearly specified.

② The invasion of moisture resistance will affect the connection H insulation performance and rust the metal parts. The constant damp heat test conditions are 90% ~ 95% relative humidity (up to 98% according to the product specification), temperature + 40 ± 20 ℃, and the test time is at least 96 hours according to the product regulations. The alternating damp heat test is more severe.

③ When the salt spray resistant connector works in the environment containing moisture and salt, the surface treatment layer of its metal structure and contact may produce electrochemical corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, salt spray test is specified. It is to hang the connector in a temperature controlled test box and spray the specified concentration of sodium chloride solution with compressed air to form a salt mist atmosphere. The exposure time is specified by the product specification, which is at least 48 hours.

④ Vibration and shock resistance to vibration and shock is an important performance of electrical connectors. It is particularly important in special application environments, such as aviation and aerospace, railway and highway transportation. It is an important index to test the robustness of mechanical structure and electrical contact reliability of electrical connectors. There are clear provisions in the relevant test methods. The peak acceleration, duration and shock pulse waveform, as well as the time of interruption of electrical continuity, shall be specified in the impact test.

⑤ Other environmental performance shall be determined according to the use requirements

Its environmental performance also includes tightness (air leakage, liquid pressure), liquid immersion (anti habitation ability of specific liquid), low air pressure, etc. state