Introduction to the technical parameters of the connector
Blog | Mar 11,2023
Electronic connectors (hereinafter referred to as connectors) can also be called plug sockets, which are widely used in various electrical circuits and play the role of connecting or disconnecting circuits.
There are many types of connectors and a wide range of applications. But if you ask what are the main technical parameters of the connector, it is estimated that few people can answer, so we also need to know the main technical parameters of the connector itself.
Insulation resistance refers to the resistance value that occurs when a voltage is applied to the insulating part of the connector to cause leakage current in or on the surface of the insulating part. It is mainly affected by factors such as insulating materials, temperature, humidity, and fouling.
The insulation resistance value provided on the connector sample is generally the index value under standard atmospheric conditions. Under certain environmental conditions, the insulation resistance value will drop to varying degrees. In addition, attention should be paid to the test voltage value of insulation resistance.
Depending on the insulation resistance (MΩ) = voltage (V)/leakage current (μA) applied to the insulator, different voltages will have different results. In the test of the connector, the applied voltage generally has three levels 10V, 100V, and 500V.
The withstand voltage is the critical voltage that can withstand higher than the rated voltage within a specified time between the mutually insulated parts of the contact pair or between the insulated part and the ground without breakdown.
It is mainly affected by contact pair spacing and creepage distance and geometry, insulator material and ambient temperature and humidity, and atmospheric pressure.
Any connector is inseparable from the current when it is working, and there is a risk of fire. Therefore, the connector is not only required to be able to prevent ignition but also required to be able to self-extinguish in a short time once it is ignited and caught fire.
When selecting, pay attention to the selection of electrical connectors with flame-retardant and self-extinguishing insulating materials.
Single leg separation force and total separation force
The contact pressure in the connector is an important indicator, which directly affects the size of the contact resistance and the wear of the contact pair. In most structures, it is quite difficult to directly measure the contact pressure. Therefore, the contact pressure is often indirectly measured by the single-leg separation force.
For circular pinhole contact pairs, standard pins with specified weights are usually used to test the ability of female contacts to hold weights. Generally, the diameter of the standard pins is -5μm, which is the lower limit of the diameter of male contacts. The total separation force is generally twice the sum of the upper-line separation forces of the individual feet.
When the total separation force exceeds 50N, it is quite difficult to use manual insertion and extraction. Of course, for some test equipment or occasions with special requirements, zero insertion force connectors, automatic fall-off connectors, etc. can be selected.
Environmental parameters mainly include ambient temperature, humidity, sudden temperature changes, atmospheric pressure, and corrosive environment. The environment in which the connector is used, stored, and transported has a significant impact on its performance, so the corresponding connector must be selected according to the actual environmental conditions.
The metal material and insulating material of the connector determine the working environment temperature of the connector. The high temperature will destroy the insulating material, causing insulation resistance and voltage resistance to decrease; for metals, high temperature can cause the contact pair to lose elasticity, accelerate oxidation and cause coating deterioration. The usual ambient temperature is -55~100°C, which may be higher on special occasions.
The relative humidity is greater than 80%, which is the main cause of electrical breakdown. The humid environment causes the absorption and diffusion of water vapor on the surface of the insulator, which can easily reduce the insulation resistance to below the MΩ level.
Long-term exposure to high-humidity environments will cause physical deformation, decomposition, and release of products, resulting in breathing effects, electrolysis, and corrosion. and crack.
Especially for the connectors outside the equipment, it is often necessary to consider the environmental conditions of humidity, water seepage, and pollution. In this case, a sealed connector should be selected. For watertight and dust-tight connectors, the shell protection level of GB4208 is generally used to indicate.
Rapid Temperature Change
The sudden change of humidity test is to simulate the actual use of the connector equipment in a cold environment to a warm environment or to simulate the rapid change of the ambient temperature of a space vehicle or a probe. Rapid temperature changes may crack or delaminate the insulating material.
At high altitudes where the air is thin, the plastic emits a gas that pollutes the contact pairs, increases the tendency of corona generation, reduces the withstand voltage performance, and causes short circuit failures in the circuit. When the high altitude reaches a certain value, the performance of the plastic becomes worse. Therefore, when using unsealed connectors at high altitudes, derating must be used.
According to the different corrosive environments of the connector, choose the connector with the corresponding metal, plastic, and plating structure, such as the connector used in the salt spray environment, if there is no anti-corrosion metal surface, the performance will deteriorate rapidly.
In an environment containing considerable concentrations of SO2, it is not suitable to use connectors with silver-plated contact pairs. Mold is also a significant problem in hot flash areas.
I hope this article can help customers better understand connectors. For practitioners in the connector industry, some general parameters of connectors should be very familiar. Improving the reliability of the connector is firstly the responsibility of the manufacturer. Only through the joint efforts of both the manufacturer and the user can the function of the connector be maximized.
Zhejiang Lianhe Electronics Co., Ltd. is a professional manufacturer of electronic connectors, automotive connectors, and other products
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