What are the basic properties of connectors?

What are the basic properties of connectors?
  • April 18, 2023
What are the basic properties of connectors?

The basic performance of the connector can be divided into three categories: mechanical properties, electrical properties and environmental performance.

First, the mechanical properties.
1. Plugging force. Insertion force is divided into insertion force and pull-out force (separation force), the two requirements are different. From the point of view of use, the insertion force should be small, while the separation force if too small, it will affect the reliability of the contact. Therefore, there is a maximum insertion force and minimum separation force in the relevant standards.

2. Mechanical life. Mechanical life is actually an indicator of durability (durability), and it is called mechanical operation in the international standard GB5095. It is inserted and pulled out once as a cycle, in the specified plugging cycle after the connector can normally complete its connection function as the basis for judging.

Connector insertion and removal force and mechanical life with the quality of the contact parts of the coating and the size of the contact arrangement accuracy.

Second, the electrical performance.
1. Contact resistance. Connector contact resistance from a few milliohms to dozens of milliohms ranging. High-quality connectors should have a low and stable contact resistance.
2. Insulation resistance. Measuring the connector between the contact parts and between the contact parts and the shell insulation performance indicators, the order of magnitude of hundreds of megohms to thousands of megohms ranging between.
3. Electrical strength. Or voltage resistance, dielectric withstand voltage, is a characterization of the connector between the contact parts or between the contact parts and the shell to withstand the rated test voltage capacity.
4. Other electrical properties. EMI leakage attenuation is the evaluation of the connector's electromagnetic interference shielding effect, generally in the 100Mhz to 10Ghz frequency range. For RF coaxial connectors, there are special resistance, insertion loss, reflection coefficient, voltage standing wave ratio (VSWR) and other electrical indicators. Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signal, accordingly, in the electrical performance, in addition to the special resistance, but also the emergence of crosstalk (crosstalk), transmission delay (delay), time lag (skew) and other new electrical indicators.

Third, the environmental performance.
1. Temperature resistance. The maximum operating temperature of the connector is currently 200 ° C (except for a few high-temperature special connectors), the minimum temperature of -65 ° C. As the connector works, the current at the contact point generates heat, resulting in temperature rise, so it is generally believed that the operating temperature should be equal to the ambient temperature and the temperature rise of the connection. In some specifications, the connector is clearly specified in the rated operating current to allow the highest temperature rise.
2. Moisture resistance. Moisture intrusion will affect the insulation performance of the connector, and rust metal parts. Constant damp heat test conditions for the relative humidity of 90% to 95% (a sentence product specifications, up to 98%), temperature +40 ± 20 ° C, the test time according to product regulations, a minimum of 96 hours. Alternating heat and humidity test is more severe.
3. Salt spray resistance. Connector in the environment containing moisture and salt work, its metal structure, contact parts surface treatment layer may produce galvanic corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the ability of the connector to withstand this environment. Salt spray test is specified. It is the connector suspended in a temperature-controlled test chamber, with a prescribed concentration of sodium chloride solution with compressed air spray, the formation of salt spray atmosphere, the exposure time has product specifications, at least 48 hours.
4. Vibration and shock resistance. Vibration and shock resistance is an important performance of the connector, in special applications such as aviation and aerospace, rail and road transport is particularly important, it is an important indicator to test the robustness of the connector mechanical structure and electrical contact reliability. There are clear provisions in the relevant test methods. Shock test should be specified in the peak acceleration, duration and shock pulse waveform, as well as the time of electrical continuity interruption.
5. Other environmental performance. According to the applicable requirements, the connector also has sealing (air leakage, liquid pressure), liquid impregnation (the ability to resist the vices of a particular liquid), low air pressure, etc.