Basic performance and working principle of connector

How the connector works

You may not know more about connectors. The so-called connector is two or several containers interconnected below the liquid surface. The liquid level is equal with the same liquid and the pressure on the liquid level is equal.

(1) The connector contains the same liquid, but the pressure on the liquid level is different, then the pressure difference of the liquid level is equal to the pressure difference caused by the liquid level difference between the two vessels of the connector.

(2) The pressure on the connector liquid level is equal, but there are different liquids on both sides which are not mixed with each other. The height of the two liquid levels is inversely proportional to the liquid density from the parting interface.

The principle of connector is widely used in engineering. For example, various liquid level meters (water level gauge, oil level gauge, etc.), mercury vacuum gauge, liquid column type air pressure gauge, differential pressure gauge, etc., are all made by using the principle of connecting device.

By understanding the definition and working principle of connectors, it will help us to better understand and develop the market of connectors.

Basic performance of connectors

The basic performance of connector knowledge connector can be divided into three categories: mechanical performance, electrical performance and environmental performance. Another important mechanical property is the mechanical life of the connector. Mechanical life is actually a durability index, which is called mechanical operation in the national standard gb5095. It is a cycle of insertion and pull-out, and the connector can normally complete its connection function (such as contact resistance value) after the specified plug-in cycle.

Connector

1. mechanical performance is important for mechanical performance of the connection function. The plug-in force is divided into insertion force and pull out force (pull-out force is also called separation force), and the requirements of both are different. The maximum insertion force and the minimum separation force are specified in the relevant standards, which indicates that the insertion force is smaller from the perspective of use (thus the structure with low insertion force LIF and ZIF without insertion force), and if the separation force is too small, the contact reliability will be affected. The plug force and mechanical life of the connector are related to the coating quality (sliding friction coefficient) and the alignment accuracy of the contact structure (positive pressure).

2. the main electrical performance of the electrical performance connector includes contact resistance, insulation resistance and resistance strength.

① The high quality contact resistance connector shall have low and stable contact resistance. The contact resistance of the connector varies from a few to dozens of milliohms.

② The insulation resistance measures the insulation performance between the contact parts of the electrical connector and between the contact and the shell, and its order of magnitude is from hundreds of megohm to several gigaohms.

③ The resistance strength, or resistance to voltage and dielectric voltage, is the ability to withstand the rated test voltage between connector contacts or between contact parts and shell.

④ Other electrical properties.

The leakage attenuation of EMI is to evaluate the shielding effect of the connector. The leakage attenuation of EMI is to evaluate the shielding effect of the connector. Generally, it is tested in the frequency range of 100mhz-10ghz.

For RF coaxial connectors, there are also electrical indexes such as characteristic impedance, insertion loss, reflection coefficient, VSWR and so on. Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signal, a new type of connector, namely high-speed signal connector, has appeared. Correspondingly, in the aspect of electrical performance, in addition to the characteristic impedance, there are also some new electrical indicators, such as crosstalk, delay, and delay, etc.

3. the common environmental performance includes temperature resistance, humidity resistance, salt fog resistance, vibration and impact resistance.

① The maximum temperature of the connector is 200 ℃ (except for a few high temperature special connectors) and the lowest temperature is -65 ℃. Because the current generates heat at the contact point during the operation of the connector, the temperature rise is caused. Therefore, it is generally considered that the working temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact. In some specifications, the maximum temperature rise allowed by the connector at rated operating current is specified. ② The invasion of moisture resistance will affect the insulation performance of connection h and rust metal parts. The constant humidity and heat test conditions are 90% - 95% relative humidity (up to 98% according to the product specification), and the temperature +40 ± The test time is 20 ℃, and the test time is 96 hours at least according to the product regulations. The alternating humidity and heat test is more severe. ③ When the salt spray resistant connector works in the environment containing moisture and salt, the surface treatment layer of metal structure and contact parts may produce electrochemical corrosion, which will affect the physical and electrical properties of the connector. In order to evaluate the ability of electrical connectors to withstand this environment, salt spray test is specified. It is to hang the connector in a temperature controlled test chamber, and spray out sodium chloride solution with specified concentration with compressed air to form a salt fog atmosphere, and its exposure time is specified by product specification, at least 48 hours. ④ Vibration and shock resistance and shock resistance are important performance of electrical connectors. They are especially important in special application environment such as aviation and space, railway and highway transportation. It is an important index to check the mechanical structure of electrical connectors and the reliability of electrical contact. There are clear provisions in the relevant test methods. Peak acceleration, duration and pulse wave form, and time of electrical continuity interruption shall be specified in impact test.

⑤ Other environmental properties of electrical connectors are sealing (air leakage, liquid pressure), liquid immersion (the ability to resist the evil of specific liquids), low pressure, etc.