Introduction to the basic performance of the connector

The basic performance of connectors can be divided into three categories: mechanical, electrical, and environmental. Another important mechanical property is the mechanical life of the connector. Mechanical life is actually an indicator of durability. It is a cycle of one engagement and separation to judge whether the connector can normally complete its connection function (such as contact resistance value) after the specified engagement and separation cycles.



1. Mechanical properties In terms of the connection function, the insertion force is an important mechanical property. The insertion force is divided into the insertion force and the extraction force (the extraction force is also called the separation force), and the requirements of the two are different. There are maximum insertion force and minimum separation force regulations in the relevant standards, which indicates that the insertion force is small from the point of view of use (thereby having a low insertion force LIF and a structure without ZIF insertion), and if the separation force is too small, It will affect the reliability of the contact. The insertion force and mechanical life of the connector are related to the plating quality (sliding friction coefficient) of the contact structure (positive pressure) contact portion and the dimensional accuracy (alignment) of the contact arrangement.



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 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 indicator of the insulation performance between electrical connector contacts and between the contacts and the casing, in the order of hundreds of megaohms to several gigaohms.



3 Resistance to electric strength, or withstand voltage, dielectric withstand voltage, is the ability to characterize the rated test voltage between connector contacts or between contacts and housing.



4 other electrical properties.



The electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector. The electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector, and is generally tested in the frequency range of 100 MHz to 10 GHz.



For RF coaxial connectors, there are electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and 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 appeared. Correspondingly, in addition to characteristic impedance, some new electrical indicators have appeared in electrical performance. Such as crosstalk, delay, skew, etc.



3. Environmental performance Common environmental properties include temperature resistance, moisture resistance, salt spray resistance, vibration and shock.



1 Temperature resistance The current maximum operating temperature of the connector is 200 ° C (except for a few high temperature special connectors), the lowest temperature is -65 ° C.



Since the current generates heat at the contact point when the connector is in operation, resulting in a temperature rise, it is generally considered that the operating temperature should be equal to the sum of the ambient temperature and the junction temperature rise. In some specifications, the maximum temperature rise allowed by the connector at rated operating current is specified. 2 Intrusion of moisture-resistant moisture will affect the insulation performance of the joint h and corrode metal parts. Constant damp heat test conditions are relative humidity of 90% to 95% (up to 98% according to product specifications), temperature +40 ± 20 ° C, test time according to product regulations, at least 96 hours. The alternating heat and humidity test is more stringent. 3 Salt spray connector When working in an environment containing moisture and salt, the metal structure and the surface treatment layer of the contact part have more contents. Please log in to 昊华电通, which may cause galvanic corrosion and affect the physical and electrical performance of the connector. . In order to evaluate the ability of electrical connectors to withstand this environment, a salt spray test is specified. It suspends the connector in a temperature-controlled test chamber and sprays it with compressed air at a specified concentration of sodium chloride solution to form a salt spray atmosphere. The exposure time is specified by the product specification for at least 48 hours. 4 Vibration and shock Resistance to vibration and shock is an important performance of electrical connectors. It is especially important in special applications such as aerospace and aerospace, railway and road transportation. It is to verify the robustness of electrical connectors and reliable electrical contact. An important indicator of sexuality. There are clear regulations in the relevant test methods. Peak acceleration, duration, and shock pulse waveforms, as well as the time of electrical continuity interruption, should be specified in the impact test.



5 Other environmental performance According to the use requirements, other environmental properties of the electrical connector are also sealed (air leakage, liquid pressure), liquid impregnation (resistance to specific liquids), low air pressure, and the like.