1, improve the production process
Splice connectors simplify the assembly process of electronic products. Also simplifies the mass production process;
2, easy to repair
If an electronic component fails, equipped with a connector can quickly replace the failed component;
3, easy to upgrade
With technological advances, equipped with a connector can be updated when the component, a new, more perfect component instead of the old one;
4, to improve design
The use of connectors allows engineers to design and integrate new products, as well as components to form a system, there is greater flexibility.
The basic properties of connectors can be divided into three main categories: namely, mechanical properties, electrical properties and environmental properties. Another important mechanical properties is the mechanical life of the connector. Mechanical life is actually a durability (durability) indicators, in the national standard GB5095 called it mechanical operation. It is an insertion and a pull out for a cycle, in order to specify the insertion and removal cycle after the connector can normally complete its connection function (such as contact resistance value) as the basis for judgment.
1. Mechanical properties of the connection function, insertion and extraction force is an important mechanical properties. Insertion force is divided into insertion force and pull-out force (pull-out force is also known as separation force), the two requirements are different. In the relevant standards have the maximum insertion force and minimum separation force provisions, which indicates that, from the point of view of the use, the insertion force to be small (thus having a low insertion force LIF and no insertion force ZIF structure), while the separation force is too small, it will affect the reliability of the contact. The insertion and extraction force and mechanical life of the connector is related to the structure of the contact parts (size of the positive pressure) the quality of the plating on the contact parts (sliding friction coefficient) and the precision of the dimensions of the contact parts arrangement (degree of alignment).
2. Electrical performance of the main electrical properties of the connector including contact resistance, insulation resistance and electrical strength.
①Contact resistance of high-quality electrical connectors should have a low and stable contact resistance. The contact resistance of the connector from a few milliohms to tens of milliohms.
② insulation resistance measure of electrical connectors between contact parts and contact parts and shell insulation between the indicators, the order of magnitude of hundreds of megohms to thousands of megohms.
3 resistance or voltage, dielectric withstand voltage, is characterized by the connector between the contacts or contacts and shells between the ability to withstand the rated test voltage.
④Other electrical properties. EMI leakage attenuation is to evaluate the connector of electromagnetic interference shielding effect, EMI leakage attenuation is to evaluate the connector of electromagnetic interference shielding effect, generally in the 100MHz ~ 10GHz frequency range test. 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 that is a high-speed signal connector, accordingly, in terms of electrical performance, in addition to the characteristic impedance, there are some new electrical indicators, such as crosstalk (crosstalk), transmission delay (delay), time lag (skew).
3. Environmental performance of common environmental performance, including temperature, humidity, salt spray, vibration and shock.
①Temperature Currently, the maximum operating temperature of the connector is 200 ℃ (except for a few high-temperature special connectors), the minimum temperature of -65 ℃. As the connector works, the current at the point of contact to generate heat, resulting in temperature rise, so it is generally believed that the operating temperature should be equal to the ambient temperature and the temperature rise of the contact points and the sum. In some specifications, it is specified that the connector in the rated operating current under the maximum allowable temperature rise.
② Resistance to humidity and moisture intrusion will affect the connection h insulation properties, and corrosion of metal parts. Constant humidity and heat test conditions for the relative humidity of 90% to 95% (according to product specifications, up to 98%), temperature +40 ± 20 ℃, the test time according to the product, at least 96 hours. Alternating humidity and heat test is more severe.
3 salt spray connectors in the environment containing moisture and salt work, its metal structure, contact surface treatment layer may produce galvanic corrosion, affecting the connector's physical and electrical properties. In order to evaluate the ability of electrical connectors to withstand this environment, the salt spray test is prescribed. It is the connector suspended in a temperature-controlled test chamber, with a specified concentration of sodium chloride solution with compressed air spray, the formation of salt spray atmosphere, the exposure time specified by the product specification, at least 48 hours.
4 vibration and shock vibration and shock resistance is an important performance of the electrical connector, in special applications such as aviation and aerospace, rail and road transportation is particularly important, it is to test the mechanical structure of the electrical connector ruggedness and reliability of the electrical contact an important indicator. There are clear provisions in the relevant test methods. Impact test should be specified in the peak acceleration, duration and impact pulse waveform, as well as the time of electrical continuity interruption.
5 other environmental performance according to the use of requirements, electrical connectors and other environmental performance sealing (air leakage, liquid pressure), liquid impregnation (on the specific liquid vices resistance to chemical ability), low air pressure and so on.
(Example: HOLLOWAY ELECTRONIC PRODUCTS)
The division of the type of connector products, although there is some confusion, but technically, there are only two basic divisions of the connector product category:
①According to the shape of the structure: round and rectangle (cross-section);
②According to the operating frequency: low frequency and high frequency (to 3MHz as the boundary).
According to the above division, coaxial connectors belong to the round, printed circuit connectors belong to the rectangular (from the historical point of view, printed circuit connectors are indeed separated from the rectangular connectors from a class of their own), while the current popular rectangular connectors with trapezoidal cross-section, similar to the rectangular. 3MHz as the boundary between the division of low-frequency and high-frequency and radio wave frequency division is also basically the same.
As for the other according to the use, installation, special structure, special performance, etc. can also be divided into many different types, and often appear in publications and manufacturers of promotional materials, but generally only in order to highlight the characteristics and use of a basic classification is still not beyond the above principles of division.
Taking into account the technological development of the connector and the actual situation, from its generality and the relevant technical standards, the connector can be divided into the following categories (subclasses):
① low-frequency circular connectors;
② rectangular connectors;
③ Printed Circuit Connectors;
④ RF coaxial connectors;
⑤ Fiber optic connectors. Fiber optic connectors.