Reliability of Connectors

The basic property of the connector can be divided into three categories: mechanical property, electrical property and environmental property. Another important mechanical property of the connector is mechanical life. The mechanical life a kind of indicator of durability and is known as mechanical operation in GB5095. It can be judged according to the connection function (such as contact resistance value) after the specified loop of insertion and extraction (one-time insertion and one-time extraction as a loop).

1．Mechanical Property

The insertion and extraction force is an important mechanical property with regard to connection function and is divided into insertion force and extraction force (also known as separating force) with different requirements. The maximum insertion force and minimum separating force are specified by the related standard. It is shown that the insertion force should be small (low insertion force LIF and zero insertion force ZIF) and the reliability of contacts can be affected if the separating force is too small. The insertion and extraction force and mechanical life of the connector is related to contact structure (value of positive pressure), quality of coating of contact position (coefficient of sliding friction) and dimensional accuracy of contact (degree of alignment).

2．Electrical Property

The main electrical property of the connector includes contact resistance, insulation resistance and dielectric strength.

(1) Contact Resistance: The high-quality electrical connector has low and stable contact resistance. The contact resistance of the connector is from several milliohms to tens of milliohms.

(2) Insulation Resistance: It is a measurable indicator for the insulating property between the contacts of electrical connectors as well as the contact and shell and is from hundreds of megohms to thousands of megohms.

(3) Dielectric Strength: It represents the rated withstanding voltage between the contacts of electrical connectors as well as the contact and shell.

(4) Other Electrical Properties

The leakage of electromagnetic interference can be used to evaluate the EMI shielding effect. Generally it is tested in the frequency range of 100MHz-10GHz.

With regard to RF connector, the electrical indicators include characteristic impedance, insertion loss, reflection coefficient, voltage standing wave ratio (VSWR), etc. With the development of digital technology, new connectors—high-speed signal connectors are developed for the purpose of connection and transmission of high-speed digital pulse signal. In the aspect of electrical property, there are some new electrical indicators such as crosstalk, delay, skew, etc. except characteristic impedance.

3. Environmental performance

Common environmental performance, including temperature, humidity, salt fog, vibration, and shock.

(1)Currently connector ① temperature maximum operating temperature of 200 ℃ (except for a small number of special high-temperature connector), the minimum temperature is -65 ℃. Since the connector is working, current generates heat at the contact point, leading to temperature rise, it is generally considered to be equal to the ambient temperature of the operating temperature and the temperature rise of the junction and. In certain specification, specify the maximum temperature rise connector rated operating current allowed

(2)moisture intrusion of moisture will affect the connection h insulation and corrosion of metal parts. Damp heat test conditions for a relative humidity of 90% to 95% (based on product specification, up to 98%), the temperature of + 40 & plusmn; 20 ℃, test time by product regulations, 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, provides for the salt spray test. It is suspended in the connector temperature controlled test chamber, with a compressed air discharge with a predetermined concentration of sodium chloride solution to form a salt spray atmosphere, and for a time specified by the product specifications, at least 48 hours.

(4)vibration and shock resistance to vibration and shock are important properties of electrical connectors, 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 robustness and reliable electrical contact an important indicator. In the relevant test methods are clearly defined. Impact test shall be provided that the peak acceleration, duration and impact pulse shape, 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.