Performance indicators of connectors
When selecting various types of connectors, such as USB, HDMI, D-Sub, etc., it is easy to see the advantages of the performance indicators marked, as they are very similar. This article will start from the basic performance of three connectors and conduct in-depth analysis around different indicators under performance.
The insertion and extraction forces are divided into insertion force and extraction force, and the requirements for the two are different. In relevant standards, there are provisions for maximum insertion force and minimum separation force, which indicates that the insertion force should be 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 durability indicator. It is evaluated based on whether the connector can complete its connection function normally after a specified insertion and extraction cycle, with one insertion and one extraction as a cycle.
The insertion and extraction force and mechanical life of connectors are related to the coating quality of the contact part of the contact structure and the accuracy of the contact arrangement size.
High quality electrical connectors should have low and stable contact resistance. The contact resistance of connectors varies from a few milliohms to tens of milliohms.
The index that measures the insulation performance between the contacts of electrical connectors and between the contacts and the shell, ranging in order of magnitude from hundreds of megaohms to thousands of megaohms.
Also known as voltage resistance or dielectric withstand voltage, it represents the ability of a connector to withstand the rated test voltage between contacts or between contacts and the shell.
Electromagnetic interference leakage attenuation is the evaluation of the electromagnetic interference shielding effect of a connector. Electromagnetic interference leakage attenuation is the evaluation of the electromagnetic interference shielding effect of a connector, generally tested in the frequency range of 100MHz to 10GHz. For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, voltage standing wave ratio, etc.
At present, the maximum working temperature of the connector is 200 ℃, and the minimum temperature is -65 ℃. Due to the heat generated by the current at the contact point during the operation of the connector, resulting in a temperature rise, it is generally believed that the working temperature should be equal to the sum of the ambient temperature and the contact temperature rise. In certain specifications, the maximum allowable temperature rise of connectors under rated operating current is clearly specified.
The invasion of moisture can affect the insulation performance of connectors and corrode metal parts.
When a connector works in an environment containing moisture and salt, the surface treatment layer of its metal structure and contact parts may produce electrochemical 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 suspends the connector in a temperature controlled test chamber to form a salt mist atmosphere, and its exposure time is specified by product specifications, at least 48 hours.
Vibration and shock resistance is an important performance of electrical connectors, which is an important indicator for testing the robustness of the mechanical structure and electrical contact reliability of electrical connectors. There are clear provisions in the relevant test methods. The peak acceleration and the time of electrical continuity interruption should be specified in the impact test.
According to usage requirements, other environmental properties of electrical connectors include sealing, low air pressure, etc.