The basic performance of connectors can be divided into three categories: mechanical, electrical and environmental performance.
1. Mechanical properties? In terms of the connection function, the insertion 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), the requirements of the two are different. In the relevant standards, the maximum insertion force and the minimum separation force are specified, which means that from the use point of view, the insertion force is small (thereby having a low insertion force LIF and no insertion force ZIF structure), and if the separation force is too small, It will affect the reliability of the contact.
Another important mechanical property is the mechanical life of the connector. The mechanical life is actually a durability index, which is called mechanical operation in the national standard GB5095. It is based on one cycle of insertion and one time of withdrawal to determine whether the connector can normally perform its connection function (such as contact resistance value) after a specified plug cycle. The insertion force and mechanical life of the connector are related to the plating quality (the sliding friction coefficient) at the contact portion of the contact structure (positive pressure) 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 several tens of milliohms. 2 Insulation resistance Measure the index of insulation performance between the contact parts of the electrical connector and between the contact part and the housing, and its magnitude is in the order of hundreds of megaohms to several thousand megaohms. 3 Electrical 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. 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. Generally, it is tested in the frequency range of 100 MHz to 10 GHz.
For RF coaxial connectors, there are also electrical specifications 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, there has emerged a new type of connector, that is, a high-speed signal connector. Accordingly, in terms of electrical performance, in addition to the characteristic impedance, some new electrical indicators have emerged. Such as crosstalk, delay, and skew.
3. Environmental Performance Common environmental performance includes resistance to temperature, humidity, salt fog, vibration, and shock.
1 Temperature resistance The current maximum operating temperature of the connector is 280°C (except for a few high temperature special connectors), with a minimum temperature of -65°C. As the connector works, the current generates heat at the contact point, resulting in temperature rise, so it is generally believed that the operating temperature should equal the sum of the ambient temperature and the temperature rise of the contact. In some specifications, the maximum allowable temperature rise of the connector at the rated operating current is specified.
2 Ingress of moisture-resistant moisture will affect the insulation performance of the connection h and corrode metal parts. The constant humidity and heat test conditions are relative humidity of 90%~95% (up to 98% according to product specifications), temperature of +40°C, 20°C, and test time of at least 96 hours according to product specifications. Alternating heat and humidity tests are more severe. 3 Salt-tolerant connectors When working in environments containing moisture and salt, the metal structures and contact surfaces of the contacts may cause galvanic corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the ability of the electrical connector to withstand this environment, a salt spray test was specified. It suspends the connector in a controlled temperature test chamber and uses a predetermined concentration of sodium chloride solution to be sprayed with compressed air to form a salt spray atmosphere. The exposure time is specified by the product specification and is at least 48 hours. 4 Vibration and Shock Resistance Vibration and impact are important properties of electrical connectors and are particularly important in special applications such as aeronautics, aerospace, railways and road transport. It is a test of the ruggedness and electrical contact reliability of mechanical structures of electrical connectors. The important indicator of sexuality. There are clear rules in the relevant test methods. The peak acceleration, duration, and shock pulse waveform, as well as the time of electrical continuity interruption, should be specified in the impact test.
5 other environmental performance? According to the requirements of use, other environmental performance of the electrical connector is also sealed (air leakage, liquid pressure), liquid impregnation (tolerant to specific liquids tolerance), low pressure and so on.