Two - way trigger diode, also known as two - end ac device (DIAC), and two - way thyristor at the same time.Because of its simple structure and low price, it is often used to trigger the bidirectional thyristor, and can also constitute overvoltage protection circuits.Construction, symbol and equivalent circuit of a bidirectional trigger diode.
Also commonly used in the overvoltage protection, timing, shift equal circuit, Figure 2 is the overvoltage protection circuit composed of bidirectional trigger diode and bidirectional thyristor.When the transient voltage exceeds the DIAC and Ubo, the DIAC quickly conducts and triggers the bidirectional thyristor to also conduct, so that the following load is protected from overvoltage damage.
DO-35,DIACS,DO-35 Diode,DO-35 package,Small Signal Diode Changzhou Changyuan Electronic Co., Ltd. , https://www.changyuanelectronic.com
In order to further promote the development of Ningbo's semiconductor lighting industry and accelerate the construction of a resource-saving society, according to the National Medium- and Long-Term Science and Technology Development Plan (2006-2020) and the 11th Five-Year Plan for Ningbo's National Economic and Social Development The Outline and the "Eleventh Five-Year Plan for Ningbo Industrial Development" and "Ningbo Medium and Long-term Science and Technology Development Plan (2006-2020)" are compiled.
1. Ningbo has a good foundation for the semiconductor lighting industry.
Light Emitting Diode (LED) was born in the early 1960s. It is a new type of solid-state cold light source with a variety of yellow, orange, red, blue, green and white light colors. It has high luminous efficiency, low power consumption, low maintenance cost, high dimensional impact resistance and shock resistance, low heat, no infrared and ultraviolet radiation. At present, it is mainly used in mobile phone backlights, displays, signals, architectural landscapes, indications, special lighting, etc., and is increasingly expanding into general lighting, LCD backlighting, automotive lighting and other fields. The semiconductor lighting industry has a long industrial chain, which mainly includes upstream raw materials, equipment and epitaxial growth, midstream chip manufacturing, downstream LED packaging and application product production. The upstream link (epitaxial growth) is the most technically important part of the semiconductor lighting industry chain and has the greatest impact on the quality of the final product. To a certain extent, the quality of the extension directly determines the quality and final application of subsequent chips, packages and application products; The middle reaches (chip preparation) is a capital and technology-intensive industry with high investment intensity and slow results; the downstream (LED packaging and application) technology content is relatively low, which is the field with low investment intensity, largest scale and fastest development. Among them, white LED is the foundation of semiconductor lighting and the development of industry, and it is also the fastest growing field in recent years.
Ningbo LED industry mainly focuses on LED packaging and LED lighting applications. LED application products such as lamps and flashlights occupy an important position in China. Other industries have a good foundation
1, LED package
Ningbo's LED packaging industry has formed a certain scale, with more than 10 companies, the overall packaging capacity is about 160 KK / month, the annual output is about 2 billion. The enterprise has a high level of technology and a large scale, and it has strong competitiveness in China.
2, LED application
Ningbo LED application is mainly composed of more than 1,000 lighting companies. It has become the largest lighting production supporting base and distribution center for lighting products in the country, and is one of the most important export bases. At present, the lamps and lanterns of the city's lighting enterprises with LED as the electric light source account for about 30% of all lamps.
3. Supporting industries
Ningbo's lighting production supporting system is very complete, and the lighting design, mold manufacturing, spare parts production and procurement, packaging and transportation, etc. have formed a one-stop supply system, and all materials and components required for lighting production can be supplied locally.
In terms of LED packaging and power management, lead frames, key alloy wires, power modules, power supply drivers and control chips all have good industrial bases, especially in LED lead frames, key alloy wires, etc., which have formed a strong Market competitiveness, products can fully meet the needs of industrial development.
4. Related industries
Among the LED-related industries, the industries with the most developed and most advantageous LEDs are the LCD display and solar cell industries. Among them, the Beilun area has become one of the most important LCD industry concentration areas in China.
The main disadvantages of Ningbo LED industry are low industrial level, incomplete industrial chain, and lack of human resources. The risks are mainly from increasingly fierce industrial competition, rapid innovation, and development risks in patents and standards. .
Second, the international industry situation
1. The market potential is huge, and new product application fields are constantly emerging.
According to statistics, in recent years, the global LED market has grown at an average annual growth rate of more than 20%, of which high-brightness LEDs are growing more rapidly. By 2010, the market for high-brightness LEDs is expected to exceed $8 billion.
2. The scale of the industry continues to expand, and the pace of cooperation between internationally renowned manufacturers has accelerated markedly. Mature technologies in the industrial chain are gradually shifting to areas with low labor costs.
With the rapid development of the market, major manufacturers in the United States, Japan, and Europe have expanded their production and accelerated their market share. Japan's Nichia, Toyoda Gosei, the United States Cree, Lumileds and other internationally renowned semiconductor lighting manufacturers increased investment of more than several billion US dollars. The pace of cooperation between large international companies is accelerating, and in order to reduce production costs, in recent years, the mature industrial sectors have been mainly labor-intensive and technology-intensive industries in the middle and lower reaches of the industry, to developing countries with low labor costs. And regional transfer.
3. The pace of technological innovation has obviously accelerated, and intellectual property rights and standards have become hot spots for competition.
The pace of innovation in semiconductor lighting technology by major companies around the world is accelerating. Flip-chip soldering technology, laser stripping technology, chip micro-structure technology, photonic crystal technology, white light single-chip technology, etc. are developing rapidly, and a large number of new products are on the market.
Major international manufacturers have mastered several core patents and adopted horizontal and vertical expansion methods to deploy patent networks worldwide and to gain market share through patent licensing.
4. The governments of all countries attach importance to the increase in research and development investment.
Japan, the United States, the European Union, etc. continue to increase support and continue to increase investment in research and development. Japan began implementing the second phase of the semiconductor lighting program in 2003. At the end of 2005, the LED procurement tax exemption law was introduced. In 2004, the US Department of Energy (DOE) set up a $28 million grant to support semiconductor lighting research and development, and in 2005 approved a new energy policy bill. From 2006 to 2011, an annual arrangement of 50 million US dollars for the technology development of the Semiconductor Lighting Project (NGLI). In 2006, the US DOE decided to invest 10 million US dollars to fund five product development projects for LED lighting; the EU is also increasing its plans. Support for European LED enterprise innovation activities.
Third, the domestic industry situation
1. The market potential is huge, and the application product development and demonstration project construction has achieved remarkable results.
From 1995 to 2006, China's LED sales grew at an annual rate of more than 30%. In 2006, China's LED production reached nearly 66 billion, with sales reaching 14.6 billion yuan. In 2006, domestic high-brightness LED sales were about 9.8 billion yuan, an increase of 26% over 2005. The proportion of LED market also increased from 56% in 2005 to 67%. Xiamen, Shanghai, Beijing, Chongqing and other places have launched application demonstration projects, and large-scale adoption of semiconductor lighting in urban landscape lighting.
2. Private capital is actively involved, industrial investment is increasing, and there is a good industrial base.
In recent years, in the face of huge business opportunities in the semiconductor lighting industry, Hong Kong New Henderson International (Group) Co., Ltd., China Electronics Group, Xiamen Mingda Optoelectronics, Fujian Sanan Group, Dalian Luming Technology Group and other companies have carried out hundreds of millions of Entering the field with huge investments ranging from several billion yuan. Venture capital funds have also shown a high degree of attention to LED projects and actively involved in the industrialization of cutting-edge technologies.
3. Major breakthroughs in key technologies and equipment for industrialization
The domestic power chip for white light illumination has been successfully developed, and the indicators have reached the international advanced level, which has changed the situation of completely relying on imports. In 2005, domestic high-brightness chips have occupied 37% of the domestic market, often in power-type packaging, white LED lighting The efficiency has reached 50 lm/W and has entered the international advanced level. Substantial progress has been made in the development of key equipment such as MOCVD machines, dicing machines, and sorting machines for semiconductor lighting production.
4. The integration of resources related to the semiconductor lighting industry chain has become inevitable, and some regions are forming their own industrial characteristics.
Several domestic research units in this field have established cooperative relationships with some places to jointly develop semiconductor lighting technologies and products. At present, from the national point of view, the Pearl River Delta, the Yangtze River Delta, Fujian and Jiangxi, and the Bohai Bay have initially formed four regions with good industries and R&D bases. Each region has formed a relatively complete industrial chain.
Fourth, planning principles
1. Market orientation, both far and near
Guided by market demand, we will strive to create a good industrial environment, cultivate a batch of enterprises as soon as possible, and continue to realize the industrialization of mature technologies. While making bigger and stronger industrial advantages, we must plan for the long-term, plan the development of LED industry chain and related supporting industries, and combine recent interests with long-term development.
2. Introduce cooperation and focus on innovation
Based on Ningbo's existing semiconductor lighting industry's base storage technology level and resource status, it will integrate resources on a global scale, strengthen interaction and cooperation with advantageous regions, and integrate and introduce simultaneously; at the same time, highlight mechanism innovation and actively explore new development ideas and New mode.
3. Highlight the characteristics and focus on the leap
Adhere to the principle of "doing something, doing something wrong", "limited goals, and highlighting key points", and form an industrial scale and competitive advantage as soon as possible in areas where Ningbo has comparative advantages. Encourage priority development for key major projects, and integrate advanced resource technologies for key advanced technologies in the field. 
