Connector knowledge The basic performance of connectors can be divided into three categories: mechanical, electrical, and environmental performance. Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability (durability) indicators, in GB GB5095 it is called mechanical operation. It is a plug-in and a pull-out as a cycle to the specified plug-in cycle after the connector can complete its connection function (such as contact resistance value) as a basis for judging.
    1. MECHANICAL PROPERTIES In terms of the connection function, the insertion force is an important mechanical property. Insertion and insertion force is divided into pull-out force (pull-out force, also known as separation force), the two requirements are different. The maximum insertion force and the minimum separation force are specified in the relevant standards, which indicates that the insertion force is small from the use point of view (thus having a low insertion force LIF and a structure having no insertion force ZIF), whereas the separation force is too small, It will affect the reliability of contact. The insertion force and mechanical life of the connector are related to the quality of the contact parts (sliding friction coefficient) of the contact structure (positive pressure level) and the dimensional accuracy of the contact arrangement (alignment).
    2. Electrical performance The main electrical properties of the connector include contact resistance, insulation resistance and electrical strength.
   ① contact resistance High-quality electrical connectors should have a low and stable contact resistance. The contact resistance of the connector ranges from a few milliohms to tens of milliohms.

   ② insulation resistance measurement of electrical connectors and contacts between contacts and shell insulation performance indicators, the magnitude of several hundred megahertz to several thousand megohms range.
   ③ Dielectric strength or resistance to voltage, dielectric pressure, is to characterize the contact between the connector or contact between the shell and the ability to withstand the rated test voltage.
   ④ other electrical properties.Electromagnetic interference leakage attenuation is to evaluate the connector's electromagnetic interference shielding effect, electromagnetic interference leakage attenuation is to evaluate the connector's electromagnetic interference shielding effect, generally in the 100MHz ~ 10GHz frequency range test. The RF coaxial connector, there are characteristic impedance, insertion loss, reflection coefficient, voltage standing wave ratio (VSWR) and other electrical indicators. As the development of digital technology, in order to connect and transmit high-speed digital pulse signal, there has been a new type of connector that is high-speed signal connector, corresponding to the electrical performance, in addition to the characteristic impedance, but also the emergence of some new electrical indicators , Such as crosstalk (crosstalk), transmission delay (delay), skew (skew) and so on.
   3. Environmental performance Common environmental performance, including temperature, humidity, salt spray, vibration and shock.
   ① temperature The current maximum operating temperature of the connector 200 ℃ (except for a few high-temperature special connector), the lowest temperature of -65 ℃. As the connector work, the current contact point in the heat, resulting in temperature rise, it is generally believed that the operating temperature should be equal to the sum of ambient temperature and contact temperature rise. In some specifications, the maximum permissible temperature rise of the connector at the rated operating current is specified.
   ② moisture moisture intrusion will affect the connection h insulation properties, and corrosion of metal parts. The constant humidity test is 90% ~ 95% relative humidity (up to 98% according to the product specification), temperature +40 ± 20 ℃, test time is 96 hours according to the product specification. Alternative damp heat test is more stringent.
   ③ salt-resistant connector in the presence of moisture and salt in the work environment, the metal structure, the contact surface treatment layer may have electrochemical corrosion, affecting the physical and electrical properties of the connector. To evaluate the ability of electrical connectors to withstand this environment, a salt spray test was specified. It is the connector hanging in the temperature controlled chamber, with a prescribed concentration of sodium chloride solution with compressed air spray, forming a salt spray atmosphere, the exposure time specified by the product specification, at least 48 hours.
   ④ vibration and shock resistance to vibration and shock is the important properties of electrical connectors, in special application environments such as aviation and aerospace, rail and road transport is particularly important, it is to test the mechanical structure of the electrical connector of the rugged and reliable electrical contact Sex of the important indicators. In the relevant test methods are clearly defined. The impulse test shall specify the peak acceleration, duration and pulse shape of the impulse, as well as the duration of the electrical continuity interruption.
   ⑤ Other environmental performance According to the requirements of the use of other electrical properties of the connector are sealed (air leakage, liquid pressure), liquid immersion (for a particular liquid resistance to abuse capacity), low pressure.