The basic performance of the connector can be divided into three categories: mechanical performance, electrical performance and environmental performance.
1. Mechanical performance As far as the connection function is concerned, the insertion and extraction force is an important mechanical performance. Insertion and extraction force is divided into insertion force and extraction force (extraction force is also called separation force), the requirements of the two are different. There are provisions for maximum insertion force and minimum separation force in the relevant standards, which shows that from the point of view of use, the insertion force should be small (there are 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. Mechanical life is actually a durability indicator, which is called mechanical operation in the national standard GB5095. It takes one insertion and one extraction as one cycle, and the judgement basis is whether the connector can normally complete its connection function (such as contact resistance value) after the specified insertion and extraction cycle.
The insertion and extraction force and mechanical life of the connector are related to the contact structure (positive pressure), the coating quality of the contact part (the sliding friction coefficient) and the dimensional accuracy of the contact arrangement (alignment).
2. Electrical properties The main electrical properties of the connector include contact resistance, insulation resistance and dielectric strength.
Electrical connectors with high-quality contact resistance 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 a measure of the insulation performance between electrical connector contacts and between the contacts and the shell, and its magnitude ranges from hundreds of megohms to several thousand megohms.
③ Dielectric strength, or withstand voltage, dielectric withstand voltage, is the ability to withstand the rated test voltage between the contact parts of the connector or between the contact part and the shell.
Four other electrical properties.
EMI leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector, and the electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector, and it is generally tested in the frequency range of 100MHz~10GHz.
For radio frequency coaxial connectors, there are also 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 terms of electrical performance, in addition to characteristic impedance, some new electrical Indicators, such as crosstalk, transmission delay, skew, etc.
3. Environmental performance Common environmental performance includes temperature resistance, humidity resistance, salt spray resistance, vibration and shock resistance.
At present, the highest working temperature of the connector is 200℃ (except for a few high-temperature special connectors), and the lowest temperature is -65℃. When the connector is working, the current generates heat at the contact point, which causes a temperature rise. Therefore, it is generally believed that the working temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact point. In some specifications, the maximum temperature rise allowed by the connector under the rated operating current is clearly specified.
Second, the intrusion of moisture and moisture will affect the insulation performance of the connection h and rust metal parts. Constant humidity test conditions are relative humidity 90%-95% (according to product specifications, up to 98%), temperature +40±20℃, test time is as per product specifications, at least 96 hours. The alternating damp heat test is more stringent.
③When the salt spray resistant connector works in an environment containing moisture and salt, the surface treatment layer of the metal structure and contact parts may produce galvanic corrosion, which affects the physical and electrical performance of the connector.