Basic performance of connectors
The basic performance of connectors can be divided into three categories: mechanical performance, electrical performance, and environmental performance.
In terms of connection function, insertion and extraction force are important mechanical properties. Insertion and extraction force are divided into insertion force and extraction force (also known as separation force), and the requirements for these two are different. Relevant standards specify maximum insertion force and minimum separation force, indicating that from a usage perspective, the insertion force should be low (hence the existence of low insertion force LIF and zero insertion force ZIF structures), while if the separation force is too low, it will affect the reliability of the contact.
Another important mechanical performance characteristic is the connector's mechanical life. Mechanical life is actually a durability indicator, referred to as mechanical operation in the national standard GB5095. It is measured by one insertion and one withdrawal cycle, and the connector's ability to perform its connection function normally after a specified number of insertion and withdrawal cycles is used as the criterion for evaluation.
The insertion and extraction force and mechanical life of a connector are related to the quality of the plating at the contact points and the dimensional accuracy of the contact arrangement.
Many people may not know much about connectors. A connector is two or more containers that are interconnected below the liquid surface. They are communicating vessels containing the same liquid, with equal pressure above the liquid surface, and the liquid levels are equal.
(1) If the connector contains the same liquid but the pressure on the liquid surface is different, then the pressure difference on the liquid surface is equal to the pressure difference generated by the difference in liquid level between the two containers of the communicating vessel.
(2) The pressure on the liquid surface of the connector is equal, but there are different liquids on both sides that do not mix. The height of the two liquid surfaces from the interface is inversely proportional to the liquid density.
The principle of connectors has wide applications in engineering. For example, various liquid level gauges (water level gauges, oil level gauges, etc.), mercury vacuum gauges, liquid column pressure gauges, differential pressure gauges, etc., are all made using the principle of communicating vessels.
Understanding the definition and working principle of connectors helps us better understand and expand the connector market.
Basic performance of connectors
Connector knowledge: The basic performance of connectors can be divided into three categories: mechanical performance, electrical performance, and environmental performance. Another important mechanical performance is the connector's mechanical life. Mechanical life is actually a durability indicator, referred to as mechanical operation in the national standard GB5095. It is measured by one insertion and one withdrawal cycle, and the connector's ability to perform its connection function (such as contact resistance value) after a specified number of insertion and withdrawal cycles is used as the evaluation criterion.
connector
1. Mechanical Performance: In terms of connection function, insertion and extraction force is a crucial mechanical performance characteristic. Insertion and extraction force are divided into insertion force and extraction force (also known as separation force), and the requirements for these two are different. Relevant standards specify maximum insertion force and minimum separation force, indicating that from a usage perspective, the insertion force should be low (hence the existence of low insertion force (LIF) and zero insertion force (ZIF) structures), while too low a separation force will affect the reliability of the contact. The insertion and extraction force and mechanical life of a connector are related to the contact structure (magnitude of normal force), the quality of the plating at the contact points (coefficient of sliding friction), and the dimensional accuracy of the contact arrangement (alignment).
2. Electrical Performance The main electrical performance characteristics of connectors include contact resistance, insulation resistance, and dielectric strength.
① Contact Resistance: High-quality electrical connectors should have low and stable contact resistance. The contact resistance of connectors ranges from a few milliohms to tens of milliohms.
② Insulation resistance is an indicator that measures the insulation performance between contacts and between contacts and the housing of an electrical connector. Its order of magnitude ranges from hundreds of megohms to thousands of megohms.
③ Dielectric strength, also known as withstand voltage or dielectric withstand voltage, is a measure of the ability of a connector to withstand the rated test voltage between contacts or between a contact and the housing.
④ Other electrical properties.
Electromagnetic interference leakage attenuation is used to evaluate the electromagnetic interference shielding effect of a connector. It is generally tested in the frequency range of 100MHz to 10GHz.
For RF coaxial connectors, there are also electrical specifications such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio (VSWR). Due to the development of digital technology, a new type of connector, the 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 specifications have appeared, such as crosstalk, transmission delay, and skew.
3. Environmental performance Common environmental performance characteristics include temperature resistance, humidity resistance, salt spray resistance, vibration and shock resistance, etc.
① Temperature Resistance: Currently, the highest operating temperature for connectors is 200℃ (except for a few high-temperature special connectors), and the lowest temperature is -65℃. Because current generates heat at the contact points during connector operation, causing a temperature rise, it is generally considered that the operating temperature should equal the sum of the ambient temperature and the contact temperature rise. Some specifications explicitly define the maximum permissible temperature rise of the connector under its rated operating current.
② Moisture intrusion can affect the insulation performance of the connection and corrode metal parts. The constant humidity and heat test conditions are a relative humidity of 90%~95% (up to 98% according to product specifications), a temperature of +40±20℃, and a test time of at least 96 hours as specified in the product specifications. Alternating humidity and heat tests are even more stringent.
③ When operating in environments containing moisture and salt, salt spray resistant connectors may experience electrochemical corrosion of their metal structural components and contact surface treatment layers, affecting the connector's physical and electrical properties. To evaluate the connector's ability to withstand such environments, a salt spray test is specified. This involves suspending the connector in a temperature-controlled test chamber and spraying it with compressed air using a sodium chloride solution of a specified concentration to create a salt spray atmosphere. The exposure time is specified in the product specifications and must be at least 48 hours.
④ Vibration and Shock Resistance: Vibration and shock resistance are crucial performance characteristics of electrical connectors, especially important in specialized applications such as aviation and aerospace, railway and road transportation. They are key indicators for verifying the robustness of the connector's mechanical structure and the reliability of its electrical contacts. Relevant test methods clearly specify these requirements. Shock tests should specify the peak acceleration, duration, shock pulse waveform, and the duration of electrical continuity interruption.
⑤ Other environmental performance: Depending on the application requirements, other environmental performance of electrical connectors include sealing (air leakage, liquid pressure), liquid immersion (resistance to degradation of specific liquids), and low air pressure.
What is a connector? A connector is an electronic component that connects the flow of electricity and electrical signals. It's a component that electronic engineers frequently encounter. In China, it's also called a connector, plug, or socket, generally referring to an electrical connector. That is, a device that connects two active devices to transmit current or signals. There are many connector brands, both domestic and international.
Connectors are not static; their form and structure vary greatly depending on the application, frequency, power, and environment. For example, there are network connectors, industrial connectors, electronic connectors, mobile phone connectors, and computer connectors, each used in different fields. For instance, the connectors used for stadium lighting, hard drive connectors, and rocket ignition connectors are vastly different. However, regardless of the type of connector, it must ensure a smooth, continuous, and reliable flow of current.
The basic performance of connectors can be divided into three categories: mechanical performance, electrical performance, and environmental performance.
1. Mechanical properties. In terms of connection function, insertion and extraction force is an important mechanical property. Another important mechanical property is the mechanical life of the connector.
2. Electrical Performance. The main electrical performance characteristics of connectors include contact resistance, insulation resistance, and dielectric strength, as well as other electrical properties. For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio (VSWR). In addition to characteristic impedance, some new electrical indicators have emerged, such as crosstalk hysteresis.
3. Environmental performance. Common environmental performance characteristics include temperature resistance, humidity resistance, vibration resistance, and shock resistance. Depending on the application requirements, there are other environmental performance characteristics, such as airtightness and resistance to low atmospheric pressure.
In fact, the function of connectors is very simple: to bridge gaps in circuits or between isolated circuits, allowing current to flow and enabling the circuit to perform its intended function. Because of their ease of mass production, maintenance, upgradeability, and improved design flexibility, connectors are widely used in various fields, such as aerospace, communications, rail transportation, consumer electronics, new energy, and medical.
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