LED lighting has received wide attention as a new generation of lighting. Simply relying on LED packaging does not make good lighting fixtures. This article mainly explains how to use the LED characteristics design from the aspects of electronic circuit, thermal analysis and optics. In recent years, with the high density and high integration of electronic products, the importance of thermal solutions is increasing, and LED lighting is no exception, and thermal solutions are also needed. Although the energy loss of incandescent lamps and fluorescent lamps is large, most of the energy is directly radiated through infrared rays, and the light source generates less heat. In addition to the energy consumed by the visible light, the LEDs are converted into heat. In addition, since the LED package area is small, heat dissipation by convection and radiation is small, thereby accumulating a large amount of heat. What is the thermal solution? Next, consider how to develop a thermal solution. The thermal solution is simply to solve the various problems caused by heat. There are: 1. Bending and cracking due to thermal expansion 2. Operational obstacles in electronic circuits 3. Material quality deteriorates In addition, you will also worry if the heat will damage the device? In order to avoid these problems, it is necessary to control the temperature of the electronic equipment as much as possible, that is to say, effective heat dissipation is very important, and the focus is to consider the machine environment and installation method to develop an optimal thermal solution. The problems caused by heat are listed below. The latter part uses LED lights as an example to explain LED-related solutions. Heat caused problems 1. Bending and cracking due to thermal expansion Electronic equipment consists of multiple parts, each of which has a different material, and the scale of thermal expansion and contraction is also different. Therefore, when various materials are combined, it is possible to bend the material. When expanding, the product will crack at the joint due to excessive stress. 2. Operational obstacles in electronic circuits In general, a semiconductor element as a heat source has such a characteristic that when the temperature of a semiconductor element in an electronic device rises, the electrical impedance becomes small. In this way, it is easy to fall into a vicious cycle of "temperature rise - impedance drop - current increase - heat increase - temperature rise", and the blown phenomenon is likely to occur. 3. Deterioration of material quality In general, materials used in electronic devices are easily oxidized, and the higher the temperature, the faster the oxidation. If these materials are repeatedly subjected to high temperature oxidation, their life will be shortened. At the same time, repeated heating, multiple expansion of the material, multiple shrinkage, will reduce the strength of the material, thereby destroying the material. LED thermal solution Let's take the LED light as an example to discuss the thermal solution of LED. There are many ways to avoid the heat of electronic devices. For example, add a radiator and place a fan that can provide cold air around the heat source. The former is to increase the heat dissipation area by increasing the heat dissipation area, and the latter is to make the heat not gather around the heat source. However, as shown in the general diagram of the LED lamp of Fig. 1, the LED package cannot be directly connected to the heat sink, and the position of the fan is not installed. Moreover, the internal power supply board also generates heat, so the heat dissipation problem of the LED light can be said to be a very difficult problem. In this way, how to effectively use LED mounting materials and heat sinks becomes very important. Figure 1 LED lamp overview So how to effectively use LED mounting materials and radiators? First, we must grasp the heat transfer path that generates heat. The heat generated by the LED elements moves through the packaged wires to the board and then dissipates heat through the heat sink. The same is true of the heat generated by the power board, which is radiated to the outside through the heat sink through the air and the filling material around the board. Reverse Conducting Thyristor(RCT)
Reverse Conducting Thyristor(RCT) is also called Reverse- appreciation Thyristor.The characteristic is that a diode is connected in reverse parallel between the anode and cathode of thyristor, so that the transmitting junction of anode and cathode is short-circuited.As a result of this special circuit structure, it has high voltage resistance, high temperature resistance, short turn-off time, low switching voltage and other good performance.For example, the turn-off time of the reverse thyristor is only a few microseconds, and the working frequency is dozens of KHZ, which is better than the fast thyristor (FSCR).This device is suitable for switching power supply and UPS uninterrupted power supply. One RCT can replace one thyristor and one continuous current diode respectively.
Reverse Conducting Thyristor,Original Reverse Conducting Thyristor,New Reverse Conducting Thyristor,Reverse-Conducting Thyristor 2200V YANGZHOU POSITIONING TECH CO., LTD. , https://www.pst-thyristor.com