Jansum talks about the working principle of the Ethernet transformer filter in the network

Principle of Ethernet Transformer

For connectors, you may not know more about them. The so-called connector is two or more containers that are connected to each other below the liquid level. Connecting devices containing the same liquid and equal pressure on the liquid surface have the same liquid surface height.

(1) The pressure on the liquid surface of the connector is equal, but there are different liquids that do not mix with each other on both sides. The height of the two liquid surfaces from the interface is inversely proportional to the liquid density.​​

(2) If the connector contains the same liquid, but the pressure on the liquid surface is not equal, the pressure difference of the liquid surface is equal to the pressure difference generated by the liquid surface height difference between the two containers of the connector.

(3) The connector principle has a wide range of applications in engineering. Such as various liquid level gauges (water level gauges, oil level gauges, etc.), mercury vacuum gauges, liquid column air pressure gauges, differential pressure gauges, etc., are all made using the principle of the connector.

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

Basic Performance of Ethernet Transformer Filters

Connector knowledge The basic performance of connectors 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 takes one insertion and one extraction as a cycle, and judges whether the connector can normally complete its connection function (such as contact resistance value) after the specified insertion and extraction cycle.

RJ45 connector

  1. Electrical properties The main electrical properties of connectors include contact resistance, insulation resistance and electric strength.

①Contact 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.

②Insulation resistance is an index to measure the insulation performance between the contacts of the electrical connector and between the contacts and the shell, and its magnitude ranges from hundreds of megohms to several gigaohms.

③ Dielectric strength or withstand voltage, dielectric withstand voltage, is to characterize the ability of the connector to withstand rated test voltage between the contacts or between the contacts and the shell.

④Other electrical properties.

     2. Mechanical Properties Insertion force is an important mechanical property in terms of connection function. The insertion force is divided into the insertion force and the extraction force (the extraction force is also called the separation force), and the requirements of the two are different. In the relevant standards, there are provisions for the maximum insertion force and the minimum separation force, which means that from the point of view of use, the insertion force should be small (thereby a structure with low insertion force LIF and no insertion force ZIF), and if the separation force is too small, will affect the reliability of the contact. The insertion force and mechanical life of the connector are related to the contact structure (positive pressure), the coating quality (sliding friction coefficient) of the contact part, and the dimensional accuracy (alignment) of the contact arrangement.

The electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector, and the electromagnetic interference leakage attenuation is to evaluate the electromagnetic interference shielding effect of the connector, which is generally tested in the frequency range of 100MHz~10GHz.

For RF coaxial connectors, there are also electrical indicators such as characteristic impedance, insertion loss, reflection coefficient, and voltage standing wave ratio (VSWR). Due to the development of digital technology, in order to connect and transmit high-speed digital pulse signals, a new type of connector, namely high-speed signal connector, has appeared. Correspondingly, in terms of electrical performance, in addition to characteristic impedance, some new electrical indicators have also appeared. , such as crosstalk (crosstalk), transmission delay (delay), time delay (skew) and so on.

     3. Environmental performance Common environmental performance includes temperature resistance, humidity resistance, salt spray resistance, vibration and shock, etc.

①Temperature resistance At present, the maximum working temperature of the connector is 200°C (except for a few high-temperature special connectors), and the minimum temperature is -65°C. Since the current generates heat at the contact point when the connector is working, resulting in a temperature rise, it is generally believed that the operating temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact point. In some specifications, the maximum temperature rise allowed by the connector at the rated operating current is clearly specified. ②The intrusion of moisture resistance will affect the insulation performance of the connection h and corrode metal parts. The constant damp heat test conditions are relative humidity 90%~95% (according to product specifications, up to 98%), temperature +40±20℃, and the test time is at least 96 hours according to product regulations. The alternating damp heat test is more severe. ④Vibration and shock Vibration and shock resistance are important properties of electrical connectors, especially in special application environments such as aviation and aerospace, railway and road transportation. important indicator of sexuality. There are clear provisions in the relevant test methods. The shock test shall specify the peak acceleration, duration and shock pulse shape, as well as the time of interruption of electrical continuity. ⑤Other environmental properties According to the requirements of use, other environmental properties of the electrical connector include sealing (air leakage, liquid pressure), liquid immersion (the ability to resist deterioration of specific liquids), low air pressure, etc.

     4. When the salt spray-resistant connector works in an environment containing moisture and salt, the surface treatment layer of its metal structural parts and contact parts may cause galvanic corrosion, which affects the physical and electrical properties of the connector. To evaluate the ability of electrical connectors to withstand this environment, the salt spray test is specified. It is to hang the connector in a temperature-controlled test box, and spray the sodium chloride solution with the specified concentration with compressed air to form a salt fog atmosphere. The exposure time is specified by the product specification, at least 48 hours.