Mechanical properties of
Mechanical properties In terms of connection function, it can be divided into:
1. Plugging force: Plugging force is an important mechanical property.Plugging force is divided into insertion force and pull out force (pull out force is also called separation force), the requirements of the two are different.The maximum insertion force and minimum separation force are specified in the relevant standards, indicating that the insertion force should be small (hence the structure of low insertion force LIF and no insertion force ZIF) from a service point of view, and that the separation force should be too small, which would affect the reliability of the contact.
2. Another important mechanical performance is the mechanical life of the connector.Mechanical life is actually a durability indicator, referred to as mechanical operation in GB5095.It takes one insert and one pull out as a cycle, and the connector can normally complete its connection function (such as contact resistance value) after the specified plug and pull cycle as the judging basis.The insertion and extraction force and mechanical life of the connector are related to the structure of the contact parts (positive pressure), the coating quality of the contact parts (sliding friction coefficient) and the dimensional accuracy of the contact parts arrangement (alignment).
3. Generally, the structure and size of the connector are classified as mechanical properties.
Electrical properties
Electrical properties The main electrical properties of a connector include contact resistance, insulation resistance, and electrical strength.
1. Contact Resistance: High quality electrical connectors should have low and stable contact resistance.The contact resistance of the connector varies from a few milliohms to tens of milliohms.
2. Insulation resistance: it is a measure of the insulation performance between the contacts of electrical connectors and between the contacts and the housing. Its order of magnitude ranges from hundreds of megohm to thousands of megohm.
3. Electrical strength: also known as voltage resistance, medium voltage resistance, is a characterization of the connector between the contact parts or between the contact parts and the shell to withstand the rated test voltage.
In addition, for other types of connectors, EMI leakage attenuation is to evaluate the shielding effect of the connector. EMI leakage attenuation is to evaluate the shielding effect of the connector, which is generally tested in the frequency range of 100MHz~10GHz.
For RF coaxial connectors, there are characteristic impedance, 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 signals, a new type of connector, namely high-speed signal connector, appears. Accordingly, in terms of electrical performance, in addition to characteristic impedance, there are also some new electrical indicators, such as crosstalk, transmission delay, skew, etc.
Environmental performance
Common environmental properties include resistance to temperature, moisture, salt spray, vibration and impact.
1. Temperature resistance: the current maximum working temperature of the connector is 200℃ (except for a few high-temperature special connectors), and the minimum temperature is -65℃.As the connector works, the current produces heat at the contact point, resulting in temperature rise, so it is generally believed that the working temperature should be equal to the sum of the ambient temperature and the temperature rise of the contact point.In some specifications, the maximum permissible liter of the connector at the rated operating current is specified.
2. Humidity resistance: the invasion of moisture will affect the insulation performance of the connector, and rust metal parts.Constant humidity and heat test conditions are relative humidity 90%~95% (according to the product specification, up to 98%), temperature +40±20℃, the test time according to the product specification, at least 96 hours.The alternating humidity and heat test is more severe.
3. Salt spray resistance: when the connector works in the environment containing moisture and salt, the metal structure parts and the surface treatment layer of the contact parts may produce electrochemical corrosion, which affects the physical and electrical properties of the connector.In order to evaluate the ability of electrical connectors to withstand this environment, a salt spray test was prescribed.It is the connector is suspended in a temperature-controlled test chamber, with a specified concentration of sodium chloride solution with compressed air ejected, the formation of salt mist atmosphere, the exposure time by the product specification, at least 48 hours.
4. Vibration and impact: vibration and impact resistance is an important performance of electrical connectors, especially important in special application environments such as aviation and aerospace, railway and road transportation, it is an important indicator to test the mechanical structure of electrical connectors, robustness and electrical contact reliability.There are clear provisions in the relevant test methods.The peak acceleration, duration, impulse waveform and interruption time of electrical continuity shall be specified in the impact test.
5. Other environmental performance according to the use of requirements, other environmental performance of electrical connectors and sealing (air leakage, liquid pressure), liquid impregnation (resistance to specific liquid), low pressure, etc.
