The basic properties of the connector can be divided into three categories: the mechanical properties, electrical properties and environmental performance. Another important mechanical properties are the mechanical life of the connector. Mechanical life is actually a durability (durability) indicators. It is once engaged, is separated into a loop, to engage in a predetermined, after the separation loop connector can normally complete its connectivity features (such as contact resistance value) as the basis for evaluation.
1. Mechanical properties on connectivity, the insertion force is important to the mechanical properties. Plug into force insertion force and withdrawal force (pull force known as separation force), both requirements are different. There are standards in the maximum insertion force and a predetermined minimum separation force, which indicates that, from the use point of view, smaller insertion force (LIF thereby low insertion force and insertion force ZIF no structure), while if the separation force is too small, it will affect the contact reliability. Connector insertion force and mechanical life contact structure (positive pressure size) contacting the coating quality parts (sliding friction coefficient) and the dimensional accuracy of contact arrangement (aligned degrees) related.
2. The main electrical performance electrical performance of the connector includes a contact resistance, insulation resistance and dielectric strength.
① contact resistance of high-quality electrical connectors should have a low and stable contact resistance. Connector contact resistance from a few cents to tens milliohms range.
② measure the insulation resistance of the insulation performance metrics between the electrical connector contacts and the contact member and the housing, of the order of several hundred to several thousand megohms megohm range.
③ said dielectric strength or resistance, voltage, medium voltage, tolerance is the ability to characterize the connector between contacts or contacts with the housing rated test voltage.
④ other electrical properties.
EMI leakage attenuation of electromagnetic interference shielding effectiveness evaluation connector, EMI leakage attenuation of electromagnetic interference shielding effectiveness evaluation connector, generally in the frequency range of 100MHz ~ 10GHz test.
RF coaxial connectors, as well as the 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 signal, the emergence of a new type of connector that is high-speed signal connectors, accordingly, the electrical properties, in addition to the characteristic impedance, but also there are some new electrical indicators such as crosstalk (crosstalk), propagation delay (delay), Delay (skew) and the like.
3. Common environmental performance environmental performance including temperature, humidity, salt spray, vibration and shock.
① temperature currently connector maximum operating temperature of 200 ℃ (except a few special high-temperature connector), the lowest temperature of -65 ℃.
Since the connector is working, current generates heat at the contact point, leading to the temperature rise, it is generally considered to be equal to the ambient temperature and the temperature rise of the junction and. In some specifications, clearly defined maximum temperature rise connector rated operating current permitted. ② moisture intrusion of moisture will affect the connection h insulation properties, and corrosion of metal parts. Damp heat test conditions for a relative humidity of 90% to 95% (depending on product specifications, up to 98%), the temperature of + 40 ± 20 ℃, according to the specified test time, a minimum of 96 hours. Damp heat test is more stringent. ③ salt spray connector containing moisture and salt in the work environment, its metal structure, the contact surface treatment layer may produce galvanic corrosion, affecting the physical and electrical properties of the connector. In order to evaluate the tolerance of the electrical connector of this environment, the salt spray test prescribed. It is suspended in the connector temperature controlled test chamber, with compressed air ejection predetermined concentration with a sodium chloride solution to form a salt spray atmosphere, its exposure time defined by the product specification, is at least 48 hours. ④ vibration and shock resistance to vibration and shock are important properties of the electrical connector, such as aviation and aerospace, rail and road transport is particularly important in a particular application environment, it is to test the electrical connector mechanical structure of sturdiness and reliability electrical contact an important indicator. In the relevant test methods are clearly defined. Shock test should provide peak acceleration, duration and impulse waveform, and electrical discontinuity of time.
⑤ other environmental performance according to requirements, as well as other environmental sealing performance (air leakage, fluid pressure), liquid immersed electrical connector (abuse-resistant capabilities of the particular liquid), and low pressure.
