The basic performance of connectors can be divided into three categories: mechanical performance, electrical performance and environmental performance.
1. Mechanical performance
As far as the connection function is concerned, insertion force is an important mechanical performance. Insertion force is divided into insertion force and extraction force, the requirements of the two are different. There are provisions for large insertion force and small separation force in the relevant standards, which indicates that the insertion force is small, 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 a kind of durability index, which is called mechanical operation in the national standard GB5095. It takes one insertion and one extraction as a cycle, and judges whether the connector can normally complete its connection function after the specified insertion and removal cycle.
The insertion force and mechanical life of the connector are related to the plating quality of the contact part of the contact structure and the dimensional accuracy of the contact arrangement.
2. Electrical properties
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 varies from a few milliohms to tens of milliohms.
② Insulation resistance The index to measure the insulation performance between the contact parts of the electrical connector and between the contact parts and the housing, the order of magnitude ranges from hundreds of megohms to thousands of megohms.
③ The electric strength, or withstand voltage and dielectric withstand voltage, is the ability to withstand the rated test voltage between the contacts of the connector or between the contacts and the 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 tested in the frequency range of 100MHz ~ 10GHz.
For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio. Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signals, a new type of connector, that is, a high-speed signal connector, has appeared. Accordingly, in terms of electrical performance, in addition to characteristic impedance, some new electrical indicators have also appeared , Such as crosstalk.
3. Environmental performance
Common environmental performance includes temperature resistance, humidity resistance, vibration and shock.
① Temperature resistance At present, the high working temperature of the connector is 200 ℃, and the low temperature is -65 ℃. When the connector is working, the current generates heat at the contact point, resulting in temperature rise, so it is generally believed that the operating temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact. In some specifications, the high temperature rise allowed by the connector at the rated operating current is clearly specified.
② The intrusion of moisture resistance will affect the insulation performance of the connection and rust the metal parts. The constant humidity and heat test conditions are relative humidity 90% ~ 95%, temperature + 40 ± 20 ℃, and the test time is at least 96 hours according to product regulations. The alternating damp heat test is more severe.
③ Salt mist resistance When the connector is working in an environment containing moisture and salt, the surface treatment layer of the metal structural parts and contact parts may produce galvanic corrosion, which affects 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 hangs the connector in a temperature-controlled test chamber to form a salt spray atmosphere, and its exposure time is specified by the product specification, at least 48 hours.
④ Vibration and shock Resistance to vibration and shock is an important performance of electrical connectors. It is an important index for testing the robustness and electrical contact reliability of electrical connectors. There are clear regulations in the relevant test methods. The peak acceleration and the time of interruption of electrical continuity shall be specified in the impact test.
⑤ Other environmental performances According to the requirements of use, other environmental performances of electrical connectors include sealing and low air pressure.
