It is often said that the short life of LED lamps is mainly due to the short life of the power supply, and the short life of the power supply is due to the short life of the electrolytic capacitor. These arguments also have some truth. Because the market is flooded with a large number of short-lived and inferior electrolytic capacitors, and now they are fighting for the price, some manufacturers have adopted these inferior short-life electrolytic capacitors regardless of the quality. The result is the above conclusion.
So what is the actual situation?
1. The life of an electrolytic capacitor depends on the ambient temperature at which it operates.
How is the life of an electrolytic capacitor defined? Of course it is defined in hours. However, if the life index of an electrolytic capacitor is 1,000 hours, it does not mean that the electrolytic capacitor will be broken after a thousand hours. No, it just means that the capacity of this electrolytic capacitor is reduced by half after 1000 hours. Originally, the capacity was reduced by half. It is 20uF, and now it is only 10uF.
In addition, there is another characteristic of the life index of the electrolytic capacitor, which is to indicate the life in the case of how many degrees of working temperature. And usually it is specified as the life at 105 ° C ambient temperature.
This is because the electrolytic capacitors we use today are electrolytic capacitors using liquid electrolyte. If the electrolyte is dry, the capacitance is of course gone. The higher the temperature, the easier the electrolyte will evaporate. Therefore, the life indicator of the electrolytic capacitor must indicate the life at what ambient temperature.
So all current electrolytic capacitors are marked with a lifetime at 105 °C. For example, the most common electrolytic capacitor has a life of only 1,000 hours at 105 °C. But if you think that all electrolytic capacitors have a life of only 1,000 hours. That's a big mistake.
Simply put, if the ambient temperature is higher than 105 ° C, its life will be less than 1,000 hours, if the ambient temperature is lower than 105 ° C, then its life is higher than 1,000 hours. So is there a rough quantitative relationship between life and temperature? some!
One of the simplest and easy to calculate relationships is that for every 10 degrees increase in ambient temperature, life is reduced by half; in turn, for every 10 degrees decrease in ambient temperature, life expectancy is doubled. Of course this is just a simple estimate, but it is also quite accurate.
Because the electrolytic capacitor used for the LED driving power supply is definitely placed inside the LED lamp housing, we only need to know the internal temperature of the LED lamp to know the working life of the electrolytic capacitor.
2. What is the ambient temperature in the LED fixture?
Because LEDs and electrolytic capacitors are placed in the same housing in many fixtures, the ambient temperature is simply the same. This ambient temperature is mainly determined by the balance of heat and heat dissipation between the LED and the power supply. And the heat and heat dissipation of each LED luminaire is different, so how can we know the ambient temperature?
In fact, this problem can be reversed, that is, a well-designed LED luminaire, which allows the internal ambient temperature to be constant. This is because the junction temperature of the LED chip is the main reason for determining the light decay (life) of the LED chip. The LED junction temperature is of course related to its ambient temperature, so as long as the allowed LED junction temperature is known, it can be inferred from the inside of the LED fixture. Ambient temperature.
However, there are at least three thermal resistances, that is, the thermal resistance θjc of the LED chip to the outer casing, and the thermal resistance of the LED casing to the surface of the aluminum substrate. In fact, it passes through the solder, the copper foil, and the insulating layer to the aluminum plate, but among them The most important is the thermal resistance of the insulating layer, collectively referred to as θlv, and the third is the thermal resistance θla of the air from the aluminum plate to the blister.
Take the 3014 LED, its thermal resistance θjc is 90 ° C / W, because its power is only 0.1W, so the internal and external temperature difference is 9 ° C. The thermal resistance of the aluminum substrate is 1 ° C / W. For a 10 W luminaire, since all 10 W LEDs are mounted on the same aluminum substrate, the total temperature difference is 10 ° C, a total temperature difference of 19 ° C, the last Θla is difficult to estimate because it is related to the circulation of air. In the case where the internal air does not flow, the temperature difference is only about 1 °C, so the total is 20 °C. That is, the LED junction temperature is equal to the ambient temperature plus 20 °C.
So can the ambient temperature inside the bulb allow 105 degrees? Just look at the picture below and you will know. That is the relationship between Cree's LED chip junction temperature and light decay.
If the ambient temperature is 105 ° C, then at least 20 ° C is the junction temperature, so the junction temperature is about 125 ° C. It has not been found on this curve and can only be roughly estimated to have a lifetime of only 4,000 hours. This is absolutely unacceptable! In other words, the ambient temperature in the LED bulb must be much lower than 105 °C!
With the continuous development of technology, wireless network has become an indispensable part of our daily life. The router WiFi module is an important part of the wireless network. In this article, we will introduce the router WiFi module in detail.
First, what is the router WiFi module?
A Wireless Router module WiFi module is a device used to convert a wired network to a wireless network. It converts data from wired networks into wireless signals, allowing multiple devices to connect to the network wirelessly. A router WiFi module typically includes a wired network interface, one or more wireless network interfaces, a processor, and some memory.
Second, the working principle of the router WiFi module ARM Core Module
The working principle of the router's WiFi module can be summarized in the following steps:
1. Data collection: The router WiFi module collects data from the Internet through the wired network interface.
2. Data processing: The WiFi module of the router uses the processor to process the collected data, including data analysis, filtering and conversion.
3. Send data: The router WiFi module converts the processed data into wireless signals and sends them to the devices connected to the network through the wireless network interface.
4. Receive data: The router's WiFi module can also receive data from devices connected to the network and forward it to the wired network interface.
Iii. Functions of router WiFi module wireless router core module
1. Network connection: The router WiFi module can convert the wired network into a wireless network, enabling multiple devices to connect to the network wirelessly.
2. Network management: The router WiFi module can manage network connection, including device connection, disconnection and configuration.
3. Security protection: The router WiFi module can provide security protection functions, including network encryption, access control and firewall.
4. Signal enhancement: The router WiFi module can enhance the coverage range and signal strength of wireless signals through signal enhancement technology.
5. Network optimization: Router WiFi module can improve network performance and stability through network optimization technology.
Fourth, the application of router WiFi module
The router WiFi module is widely used in various occasions such as homes, enterprises and public places, providing users with high-speed, stable and secure wireless network services. The following are some application scenarios of the router's WiFi module:
1. Home network: The router WiFi module can provide wireless network services for home users, so that multiple devices can be connected to the network wirelessly, such as mobile phones, tablets, laptops, etc.
2. Enterprise network: Router WiFi module can provide wireless network services for enterprise users, so that employees can connect to the network anywhere in the office, improving work efficiency and convenience.
3. Public places: Router WiFi module can provide wireless network services in public places, such as hotels, cafes, airports, railway stations, shopping malls, etc.
Fifth, the development trend of router WiFi module
With the popularity of wireless networks and the continuous expansion of application scenarios, the development of router WiFi module also presents the following trends:
1. High-speed: With the development of 5G technology, the speed of router WiFi module will be faster and more stable.
2. Intelligent: The router WiFi module will be more intelligent, which can automatically adjust the signal strength and coverage, improve the network performance and stability.
3. Security: The router WiFi module will pay more attention to network security and provide more complete security protection functions to ensure users' network security.
4. Multi-functional: Router WiFi module will have more functions, such as Internet of Things connection, voice control, smart home, etc.
Router WiFi module is one of the important components of wireless network, it can convert wired network into wireless network, and provide users with high-speed, stable and secure wireless network services. With the popularity of wireless network and the continuous expansion of application scenarios, the development of router WiFi module also shows the trend of high-speed, intelligent, secure and multi-functional.
Wireless Router Module,Arm Core Module,5G Module,Router Core Board
Shenzhen MovingComm Technology Co., Ltd. , https://www.movingcommtech.com