1. Mechanical properties

As far as the connection function is concerned, the pull-out force is an important mechanical performance. Plugging force is divided into insertion force and pull-out force (pull-out force is also called separation force), the requirements of the two are different. The maximum insertion force and minimum separation force are stipulated in the relevant standards, which indicates that the insertion force is smaller from the point of view of use (hence the structure of LIF with low insertion force and ZIF without insertion force), and if the separation force is too small, the reliability of contact will be affected.

Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability index, which is called mechanical operation in national standard GB5095. It takes one insertion and one pull-out as a cycle to judge whether the connector can normally complete its connection function (such as contact resistance value) after the specified insertion and pull-out cycle. The insertion force and mechanical life of the connector are related to the structure (positive pressure) of the contact parts, the coating quality (sliding friction coefficient) of the contact parts and the dimensional accuracy (alignment) of the contact parts.

2. Electrical Performance

The main electrical properties of connectors include contact resistance, insulation resistance and electrical strength.

Contact resistance High quality electrical connectors should have low and stable contact resistance. The contact resistance of the connector varies from several milliohms to tens of milliohms. Insulation resistance is an index to measure the insulation performance between contacts of electrical connectors and between contacts and outer shells. Its magnitude ranges from hundreds to thousands of mega-ohms. Electrical resistance, or withstand voltage, dielectric withstand voltage, is the ability to withstand rated test voltage between connector contacts or between contacts and shell. Other electrical properties. EMI leakage attenuation is to evaluate the shielding effect of the connector. EMI leakage attenuation is to evaluate the shielding effect of the connector. It is generally tested in the frequency range of 100 MHz to 10 GHz. For RF coaxial connectors, there are also electrical indicators 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, namely high-speed signal connector, has emerged. Accordingly, in terms of electrical performance, besides 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, moisture resistance, salt spray resistance, vibration and impact resistance.

1. Temperature Resistance

At present, the highest working temperature of the connector is 200 C (except for a few high temperature special connectors), and the lowest temperature is - 65 C. Because the current generates heat at the contact point when the connector works, which results in temperature rise, it is generally considered that the working temperature should be equal to the sum of the ambient temperature and the temperature rise at the contact point. In some specifications, the maximum allowable temperature rise of the connector at rated operating current is specified explicitly.

(2) Humidity resistance

Invasion of moisture will affect the insulation performance of connection h and corrode metal parts. The constant humidity and heat test conditions are 90%~95% (according to product specifications, up to 98%) and temperature + 40 +20 C. The test time is at least 96 hours according to product specifications. Alternating humidity and heat tests are more rigorous.

(3) Salt fog resistance

When the connector works in the environment containing moisture and salt, the surface treatment layer of its metal structure and contact parts may produce electrochemical corrosion, which will affect 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 prescribed.

(4) Vibration and shock

Vibration and shock resistance 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 mechanical structure and electrical contact reliability of electrical connectors. There are clear provisions in the relevant test methods. The peak acceleration, duration, impulse waveform and time of electrical continuity interruption should be specified in impact test. Other environmental performances of electrical connectors include sealing (air leakage, liquid pressure), liquid impregnation (resistance to specific liquids), low pressure and so on.