What are the electrical properties of connectors？

Contact resistance: 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.

Insulation resistance: an indicator that measures the insulation performance between the contact parts of an electrical connector and between the contact parts and the shell, ranging in magnitude from hundreds of megaohms to thousands of megaohms.

Electrical strength, also known as voltage resistance or dielectric withstand voltage, is the ability of a connector to withstand the rated test voltage between its contacts or between the contacts and the casing.

Other electrical performance

Electromagnetic interference leakage attenuation is an evaluation of the electromagnetic interference shielding effect of a connector. Electromagnetic interference leakage attenuation is an 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 (VSWR), etc. Due to the development of digital technology, a new type of connector called high-speed signal connector has emerged to connect and transmit high-speed digital pulse signals. Correspondingly, in terms of electrical performance, in addition to characteristic impedance, some new electrical indicators have also emerged, such as crosstalk, transmission delay, and delay.

Common environmental performance includes low temperature, constant humidity and heat, alternating humidity and heat, salt spray test, sulfur dioxide test, and hydrogen sulfide test.

Temperature resistance: Currently, the maximum working temperature of connectors is 200 ℃ (except for a few high-temperature special connectors), and the minimum temperature is -65 ℃. Due to the heat generated by the current at the contact point during the operation of the connector, it is generally believed that the working temperature should be equal to the sum of the ambient temperature and the temperature rise at the contact point. In certain specifications, the maximum allowable temperature rise for connectors at rated operating current is clearly specified.

The invasion of moisture resistance can affect the insulation performance of the connection and corrode the metal parts. The constant humidity test conditions are relative humidity of 90%~95% (up to 98% according to product specifications), temperature of+40 ± 20 ℃, and the test time is at least 96 hours according to product specifications. The alternating humidity and heat test is more stringent.

When salt spray resistant connectors work in environments containing moisture and salt, the surface treatment layer of their metal structural components and contact parts may produce electrochemical corrosion, which affects the physical and electrical performance of the connectors. 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, sprays out a specified concentration of sodium chloride solution with compressed air to form a salt spray atmosphere, and its exposure time is specified by the product specifications, at least 48 hours.

Vibration and shock resistance are important properties of electrical connectors, especially in special application environments such as aviation and aerospace, railway and road transportation. They are important indicators 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, duration, and waveform of the impact pulse should be specified in the impact test, as well as the time for electrical continuity interruption.

According to usage requirements, other environmental properties of electrical connectors include sealing (air leakage, liquid pressure), liquid immersion (resistance to specific liquids), low air pressure, etc.