How to choose an electronic connector?

The main consideration is the electrical continuity of the contact pairs during connector vibration, shock and impact at specific frequencies and accelerations. Under this dynamic stress condition, the contact pair will open instantly. The specified instantaneous disconnection time is generally 1 μs, 10 μs, 100 μs, 1 ms, and 10 ms. It should be noted how to judge the instantaneous failure of the contact pair. It is now generally believed that when the voltage drop across the closed contact pair (contact) exceeds 50% of the power electromotive force, it can be determined that the closed contact pair (contact) has failed. That is, there are two conditions for judging whether a transient occurs: duration and voltage drop, both of which are indispensable.

Connection mode

A connector is usually composed of a plug and a socket, wherein the plug is also called a free-end connector, and the socket is also called a fixed connector. Circuits are connected and disconnected through plugs, sockets, and plugs, resulting in various connection methods for plugs and sockets. For circular connectors, there are three main types of connections: threaded, bayonet, and pin connections. Of these, threaded connections are the most common. It has the advantages of simple processing technology, low manufacturing cost and wide application range. However, slow connections are not suitable for occasions requiring frequent plugging and fast connection. Due to the longer leads of its three bayonet slots, bayonet connections have faster connection speeds, but they are more complex and costly to manufacture. Pinball connection is the fastest of the three connection modes. It does not require rotary motion, only linear motion is required to achieve the functions of connection, disconnection and locking. Because it is a direct push-pull connection, it is only suitable for connectors with a small total separation force. This is usually more common in small connectors.

Installation method and appearance

The connector is installed with front mounting and rear mounting. Installation and fixing methods include rivets, screws, snap rings or quick locking of the connector itself. Another type of plug and socket are free-end connectors, so-called relay connectors.
The shape of the connector is constantly changing. The user mainly selects straight lines, bends, outer diameters of wires or cables, fixing requirements to the casing, volume, weight, and whether or not metal hoses need to be connected. The connectors used on the panel also need to be selected from the aspects of aesthetics, shape, and color.

Environmental parameters

Environmental parameters include ambient temperature, humidity, temperature changes, atmospheric pressure, and corrosive environments. The use, storage and transportation environment of the connector has a great impact on its performance, so the corresponding connector must be selected according to the actual environmental conditions.

Ambient temperature

The metal and insulating material of the connector determine the working temperature of the connector. High temperatures can damage edge materials, resulting in reduced insulation resistance and withstand voltage performance. For metals, high temperatures can cause contact pairs to lose elasticity, accelerate oxidation and cause coating deterioration. The normal ambient temperature is -55 ~ 100 ℃, which may be higher in special cases.

wet

Relative humidity exceeds 80%, which is the main reason for electrical breakdown. A humid environment causes water vapor to be absorbed and diffused on the surface of the insulator, which can easily reduce the insulation resistance below mω. Prolonged exposure to high humidity can cause physical deformation, decomposition, and escape of the product, resulting in respiratory effects, electrolysis, corrosion, and cracking. Especially for connectors outside the equipment, environmental conditions such as humidity, water penetration and pollution should always be considered. In this case, a sealed connector should be selected. For waterproof and dustproof connectors, the enclosure protection level of GB4208 is generally used.

The temperature changes quickly.

The rapid humidity change test simulates the actual use of connector equipment in cold to warm environments, or simulates rapid changes in the ambient temperature of spacecraft and detectors. Sudden temperature changes may cause cracking or delamination of the insulation.

Atmospheric pressure

At high altitudes where the air is thin, plastic will release gas, pollute the contact pairs, increase the tendency of corona, and reduce the withstand voltage performance, which will cause short circuit faults. When reaching a certain value at high altitude, plastic