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At present, used in electronic equipment power supply terminals has become a trend, and the power terminal device itself has also been gradually increase, and carry more power, as the terminal size bigger, the importance of them in the aspect of equipment function is more outstanding, and guarantee the product characteristic has played a more and more important role.

Continuous improvement of circuit board technology makes the panel installed on the terminal can carry current increase a lot, has breakthrough the limitation of the 110 a, far more than the previous product level, which used in the design process to the end what kind of power supply terminals to meet the requirement of the system, this problem becomes more complicated. In addition, in the different area has the different methods to measure the performance parameters, even for the same product have given nominal parameters also have quite a big difference. Thus, to achieve long-term reliability and ensure the low cost, it is very important to understand these differences.

Engineers must also consider the factor of another often overlooked, namely marketing considerations. Usually, the terminal is visible for the user, so often want to product Marketing Department in terms of appearance to match the color and style of the whole system.

The following specific introduction of the important factors influencing the terminals to choose.

Processing power factor

You first need to consider is one of the factors of power handling capacity of the device. Simply reading data sheet does not guarantee that the comparison of accurate data. The engineers must know the products listed in the manual is how to test to determine the performance data.

Currently, institutions such as UL, IEC, CSA and DIN in determining the power and performance specifications of terminal products and there is no uniform standard. Users need to understand the difference between UL and IEC specifications. In Europe the terminals of the specifications of the products adopt IEC standards, and in the United States UL standard will be used on products. The difference between the two standard is very big. Don't understand the product specification of determination method of engineer will take a considerable risk, because the device selection is likely to be short of the required power levels, or to choose devices of the specifications of the far beyond the needs of design. In Europe, the current rating of the device is by monitoring the current increase the temperature of the metal conductor. When the temperature of the metal pin higher than ambient temperature 45 ℃, surveyors will at this time as the device of the rated current value of the current (or most current value). Another is to allow the current value of the IEC specification, it is 80% of the maximum current. Instead, UL standard with the metal conductor temperature 30 ℃ higher than the ambient temperature when the current value of 90% as a device of the current nominal value. Thus, the temperature of the metal conductor section is a very important factor in all applications. For industrial equipment which is more important. Because industrial equipment often need to work in the environment of the temperature as high as 80 ℃. If the temperature of the terminal next higher than a temperature 30 ℃ or 45 ℃, so the temperature of the terminal blocks will be more than 100 ℃. Based on the selected device adopts the nominal value of type and insulation materials, products must be lower than the current rating of the work, which ensures that they can reliably work at desired temperature range. Sometimes, suitable for compact packaging device materials may not be able to meet the cooling requirement very well, so this kind of terminal device when using must be much lower than the current rating.

With enterprise globalization, the need to design can be sold on the global system, so the system is more and more designers to use the power terminal products in other countries. Due to the nominal value is used to measure the method, thus the device is lower than the nominal value to use in the design is common practice in Europe. However, many designers are not familiar with this concept in the United States, if you don't understand the difference between the standard, in the design process will be difficult.

When choosing device, often ignored the another factor is the product of the technology used. Most power terminal products still use hole connection mode. This method can provide the required mechanical support, and can guarantee and embedded in the multilayer circuit board power supply layer keep solid electrical contact. And circuit board used to connect the terminals to there are many different types of pins. Some companies provide only a single pin type, while others provide more pin products. Pin product advantage: it can make the current more evenly distributed to the circuit board line, provide more reliable mechanical stability and improve the robustness of the welding.

Exterior factors

Despite the name "power supply terminals" sounds was not beautiful, but many companies believe it is in user's affinity for product appearance and have played an important role. The power terminals must be convenient installation, because they are often installed in the front of the panel is easy to see products. In this way, marketers often want to the power terminal product appearance has certain voice. But often encounter this kind of circumstance: engineers design products can meet the demands of all mechanical and electrical parameters, but had to change due to did not meet the requirements of sales. If this happens at the end of the design cycle (often marketing family once saw the prototype), then it would be difficult to avoid a fierce debate, and could lead to rising costs and delay in delivery. In many industrial control systems, terminal blocks are often technical personnel need to be focused on one of the few parts. Despite its user interface is simple screw (mainly), but for normal operation of the equipment is very important.

In general, with the increase of current, wire become more thick, and the coarse wire fastening torque required on the terminal was also need to increase. Power terminal, therefore, need more screws and more solid insulation shell. Sometimes small screw is used to save space. In a very compact terminals products often are. Some wire reaches more than 1/4 inch in diameter, so it is difficult to deal with these small screw. When technicians need to install multiple lines and maintenance operator, to simplify the attachment by a large enough screw work can greatly save time. This is also the engineer during the design process is so important to listen to your Marketing Department as soon as possible. If the terminals must be properly polished or using the appropriate color, so as an original product requirements put forward these parameters than at the end of the development cycle to adjust them much easier.

When the terminal is used for consumption (such as high-end stereo products) products, appearance is more important. In fact, some designers tend to specify the terminal device is used for audio devices gold-plated processing, so although increased the cost and no significant increase performance, but the gold-plated did improve the appearance of the product.

Conclusion: to know the power terminal parameter measurement method is a key part of the system design. Confirm the choice of power supply terminals meet temperature range, current and voltage of power supply equipment requirement helps to ensure the long-term reliability of the system. In addition, if the choice of power supply terminal devices used to meet the market requirements of wiring technology, and in the design to ensure that the user operation is convenient, so can greatly improve the success probability of the final product.