Method for measuring the charging current of a battery

In view of the business opportunities of the entire Chaoyang industry, in order to seize the opportunity to seize more markets and create more benefits, many lighting companies are rushing to develop various road lamps to meet the needs of users, and even some companies that did not produce lighting products have also started. However, due to the difference in the level of awareness of lighting knowledge, the current situation of semiconductor lighting products chaos, some corporate products have also entered a misunderstanding, which has brought a great negative impact to the terminal customers.

Unlike traditional lighting, LED has a little light source, high brightness, narrow beam output and other characteristics. Therefore, the designers of the new LED lamps will put forward higher requirements. To make LED street lights, we must consider the full use of the limited light flux to the effective irradiation range. The street light requirement is the road surface lighting effect, the open space beyond the road surface is not the way of street light lighting. Therefore, the distribution of light is effectively controlled, so that the light emitted by the light emitting tube becomes a long strip of light that spreads along the road surface. At the same time, it is also necessary to take into account the generation of glare. At the azimuth angle of the driver's view of the lamp, The light intensity of the lamps at the angles of 80 ° and 90 ° should not exceed 30cd/1000lm and 10cd/1000lm, respectively, and regardless of the size of the light flux, the maximum light intensity at the angle of 90 ° must not exceed 1000cd. Therefore, if the optical angle is not strictly controlled, strong glare will be generated, and some high-brightness LED products will even cause certain optical radiation hazards to the human body.

Street lighting is a systematic project. To do a good job in semiconductor street lighting, we must first clearly understand the standards and requirements of road lighting and the principle of light distribution of conventional lighting lamps, the difference between the reflection of spherical surface light and the reasonable light distribution of point light sources, and the advantages and disadvantages. Complementarity, Give full play to the controllable advantages of LED point light source beam angle and the advantages of long life of cold light source.

Semiconductor LED light source has its own characteristics on the structure and optical characteristics. Therefore, semiconductor street lights should be designed according to these characteristics. Today, some manufacturers use the traditional lamp housing to replace the semiconductor wick, and heat dissipation by transition conduction can not be done. Good lamp. The problem is that the exterior shape of the lamp body must be combined with the heat dissipation of the light emitting tube, and the heat dissipation depends on the area. The surface area of the existing conventional lighting lamps is far from enough. The "Coke heat law" is to have a good natural air convection environment. The operating temperature of LED products must be basically controlled below 65 °C(the international standard is 80 °C. When the operating temperature of LED reaches 85 °C, the luminous flux will drop by half; The wavelength becomes longer, that is, the redshift; There is a risk of burning beyond 90 °C). The installation of light emitting tubes, scientific and reasonable optical light distribution, light body sealing is very important. At the same time, the light structure designed is also conducive to mass industrial production.

The heat dissipation of the light emitting tube is a key problem for semiconductor lamps. The light emitting tube is a cold light source and does not produce hot temperatures like gas discharge lamps. However, the limitations of the light effect of LED light emitting tubes today also have their own limited thermal energy. Therefore, the heat generated by the operation of the luminescent tube must be effectively emitted into the air to ensure that the luminescent tube works at a safe temperature so that the semiconductor lamp can truly reflect the advantages of long life.

It is very important for LED street lights to use light emitting tubes. Today, some manufacturers use integrated packaging 10W or more to make street lights. There are optical light distribution difficulties, glare, and overall heat dissipation difficulties. There are also modules that use 3W to 5W. The luminous tube meter has low light efficiency per watt, and there is also an overall heat dissipation problem. The price advantage under the same light flux is not obvious compared to a single 1W. Comprehensive consideration, the choice of high-power 1W light emitting tube is reasonable. From the current high power light emitting tube technology level, 1W light efficiency is relatively high, for lighting energy-saving advantages are obvious, at present, 1W is used as a road light source is more reasonable.

The light color selection of LEDs is also a factor that deserves attention. In the development of road lighting, there is a comparison between the use of yellow light and white light. Huangguang is now the mainstream high pressure sodium lamp, because it is economical energy conservation, and at the same time has excellent fogging performance, so now it has become the mainstream street lamp choice in China. In spite of this, Huang Guang also has its congenital deficiency: that is, the color reduction ability is poor. People have the feeling that under the sodium light, the color of any illuminated object is yellowish and distorted. The goal of white light is natural sunlight. Because it has the best color performance, and the sun is a kind of warm white light. Therefore, if you can achieve Heriguang's similar white light, but also take into account the advantages of Huang Guang's economic energy conservation, it will be an ideal night lighting choice. The early stage of white light is the gold halogen lamp. Although it has more than several times more color performance than yellow light, it has not been applied on a large scale because of some insurmountable technical problems with poor fogging performance and low active life. The production of LED light sources can make up for this defect. It is more appropriate to put about 3500K on the color temperature choice of LED light source, and meet the lighting requirements in bright vision and comfort. Moreover, it is feasible to develop the light effect and cost efficiency of LEDs today, and it is suitable for large-scale promotion of LED street lights.

There are different views on the use of white light above 6000 K as a light source, especially for high-power 160W or more. The use of expressway roads requires caution. According to the National Road lighting standards, the expressway and main trunk roads must use truncated or semi-truncated lamps.

Interceptor lamps: The maximum light intensity direction of the lamp is between 0 ° and 65 ° and the vertical axis of the lamp. The maximum allowable values of light intensity at the angles of 90 ° and 80 ° are 10 cd/1000 LM and 30 cd/1000 LM, respectively. Lamp. Regardless of the size of the luminous flux, its maximum light intensity in the direction of 90 ° must not exceed 1000 CD.

Semi-truncated lamps: The maximum light intensity direction of the lamp is between 0 ° and 75 ° and the vertical axis of the lamp. The maximum allowable values of light intensity at the angles of 90 ° and 80 ° are 50cd/1000lm and 100cd/1000lm, respectively. Lamp. Regardless of the size of the luminous flux, its maximum light intensity in the direction of 90 ° must not exceed 1000 CD.

Due to the long expressway road, wide road width, large traffic volume, fast speed, high visual sensitivity requirements. Therefore, the illumination, color temperature, brightness uniformity on the road, glare and other indicators require high. In order to compare with the 400W high-pressure sodium lamp, it is blindly required to require high power and high brightness. And today's LEDs are difficult in terms of light efficiency and heat dissipation costs, and it is difficult to promote cost-effective.

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