Q：Why is the LED light source better than the sodium lamp?
A： At present, the high-pressure sodium lamp and low-pressure sodium lamp commonly used in the public power street lamp industry in China, the reason why they choose to use sodium lamp is because they have the characteristics of high luminous efficiency and long life. Take the high-pressure sodium lamp as an example: the luminous efficiency is 120lm/w, and the average life can reach 2 years. However, it also has its own significant drawbacks, that is, the color temperature (K=1900/2200/2500) is too low, and the color rendering index (Ra=23/60) is too bad. In order to solve the problem that the color temperature of the high-pressure sodium lamp is low and the color of the light is severely reddish, the commonly used method is to increase the power and let the power reach 250-400W with a large amount of luminous flux to compensate for the problem of color cast of the object. The average illuminance value required by the national standard JT/T367--1997 "Technical Conditions for Highway Lighting" is mostly at 15LX and does not require high luminous flux. That is to say, in many cases, it is not necessary to use such a high-power, high-value light flux sodium lamp to illuminate, but because of the low luminous flux, all objects will be heavily discolored under the lamp and generally yellowish.
The LED street lamp produced by our company is a new type of light source with a theoretical life of more than 50,000 hours, which can be used for almost 10 years, although its luminous efficacy is lower than that of sodium lamp. However, its color temperature is much higher than that of sodium lamp. The color temperature of super bright white LED can reach 15000K, the color rendering index is close to 100, and the specific values such as color temperature can be adjusted as needed, which can choose a range that is more suitable for human eyes. Manufacture products of varying sizes. Under the condition that the color temperature is suitable, the illumination lamp with LED as the light source shows a slight illuminance, but the light color is bright and the color rendering index is high.
At present, LED has a unique advantage as the core component of the illumination source, that is, the LED light-emitting chip belongs to the solid-state light-emitting device, which has good stability and is not affected by the external environment temperature. . Compared with high-pressure sodium lamps or metal halide lamps, energy-saving lamps and other gas-emitting light sources, it is more suitable for use in natural environments with low ambient temperature in the north and large temperature changes in different seasons.
This means that, also meeting the lighting requirements of the national standard, the use of LED light source can greatly reduce the power of the illuminator, and at the same time can greatly reduce the power consumption, so The country will vigorously promote the widespread use of LED products. In order to adapt to the rapid growth of LED demand in the market, China has focused on the development of LED as one of the "31 countries encouraged to develop electronic products" and "20 kinds of electronic products and technologies that encourage foreign investment." At present, in the domestic market, LED as an illumination source has increasingly shown its unique advantages, and has begun to spread in many cities in China.
Q：What are the types of LED waterproof power supplies?
A：LED waterproof power can be divided into several categories according to circuit layout:
1. Electronic transformer step-down: This power supply layout is inefficient in that the conversion power is low, the voltage scale is narrow, usually 180~240V, and the ripple interference is large.
2, capacitor step-down: This method of LED waterproof power supply is simply affected by the grid voltage shake, power supply is low, it is not suitable for LEDs to use when flashing. Since the circuit is stepped down by the capacitor, when the flashing is applied, due to the effect of charging and discharging, the current through the LED is extremely large, and the chip is simply damaged.
3, PWM control switching power supply: At present, the LED power supply depicted by the PWM control method is more ambitious, because the output voltage or current of this LED waterproof power supply is very stable.
Q：What is LED power?
A：An LED power supply is a type of power supply that is a device that supplies power to an electronic device, also known as a power supply, deployed as a separate power supply input on the device to a separate circuit device with two or three power inputs.
According to the power supply voltage, it can be divided into high voltage 85-265V and low voltage 12-80V. Currently, the commonly used outdoor power sources use high voltage driving power sources, such as: street lights, flood lights, track lights, buried lights, corn lights; Indoor lighting is gradually driven by low voltage, such as spotlights, candle lights, panel lights, ceiling lights, bulbs, and fluorescent lights.
According to the power supply characteristics, it can be divided into constant current power supply and constant voltage power supply; constant voltage power supply is mainly used for switching power supply and power adapter, while constant current power supply is mainly used for various types of lighting, such as street light, panel light, flood light, garden light. , candle lights, fluorescent lights, ceiling lights, panel lights, spotlights; and automotive LED, electric car LED drive.
Zhongfu Optoelectronics is committed to LED low-voltage constant current power supply for 6 years, with mature technology and excellent quality. It has a superb R&D team and a complete set of production test equipment, which are sold all over the world.
Q：The difference between constant voltage power supply and constant current power supply
A：Theoretically: Constant voltage is the voltage output does not change regardless of the load. The constant current is that the current output of the power supply does not change regardless of the load. To achieve constant voltage, the internal resistance of the power supply is required to be infinitely small. No matter how the external current changes, the loop current will change, and the voltage drop will not be caused by the internal resistance of the power supply, thus ensuring a constant power supply of the power supply, and achieving constant current. It is necessary to go to the power supply with an infinite internal resistance. No matter how the external load changes, the loop resistance changes, and the relatively infinite power supply internal resistance does not cause any change in the impedance on the loop, and the coincidence obtains a constant current power supply.
However, from the power supply point of view, the realization of constant voltage and constant current circuit is different, the internal resistance of the ideal constant voltage circuit is zero, and the internal resistance of the ideal constant current circuit is infinite. That is to say, the actual so-called constant voltage or constant current circuit is limited to a limited load within a certain resistance range.
The real difference between constant voltage and constant current is the application. The signal sent by the constant voltage source can be connected in parallel with a constant load. For example, when connected to a voltmeter, an oscilloscope, an AD converter, etc., the signal sent by the constant current source cannot be used in this way; the signal sent by the constant current source is suitable for series connection. Load, but when the long-distance transmission of the slowly varying signal is that the voltage drop on the line does not affect the amount of current obtained on the load, it is obvious that the constant voltage source cannot do this. It can be seen that the essential difference between constant voltage and constant current is reflected in their application.
For the problem of constant voltage and constant current in the circuit at the same time, for the ideal resistance, constant voltage is realized to achieve constant current, but this has no practical application significance. The discussion of constant voltage and constant current only makes sense in the changing load. For a variable load, it is obvious that it is impossible to achieve both at the same time.
Q：LED driving power filling method and precautions
A：ED driver power potting glue is suitable for potting protection of general electronic components, power modules and circuit boards, as well as potting of various electronic appliances, such as switching power supply, driving power supply, automotive HID lamp module power supply, automotive ignition system module power supply. , home appliance controllers, network transformers, etc. Many customers don't know much about the operation method of LED driver power potting glue, so that the main agent after curing is too soft or the surface is too sticky. Now we will explain the specific operation of LED driver power potting glue. Method and related.
Handling of the issue:
1. Before mixing: A and B components should be fully stirred manually or mechanically to avoid performance changes due to sedimentation of the filler.
2. Mixing: Weigh the two parts in a 1:1 ratio and put them into a clean container. Stir well, the error should not exceed 3%, otherwise it will affect the performance after curing.
3. Defoaming: Natural defoaming: The uniformly mixed gel is allowed to stand for 20-30 minutes, vacuum defoaming: vacuum degree is 0.08-0.1 MPa, vacuum is taken for 5-10 minutes.
4, perfusion: the glue should be filled in the operation time, otherwise it will affect the leveling. The surface of the substrate is kept clean and dry before potting.
5, curing: room temperature or heat curing can be. The curing speed of the glue has a great relationship with the curing temperature. It takes a long time to cure in the winter. It is recommended to cure by heating. It is cured at 80 ° C for 15-30 minutes, and it usually takes about 6-8 hours to cure at room temperature.
Remember a friend who asked me before:Why do the main agent too soft when the two-component potting glue is cured, sometimes the surface is too sticky?
The first method: rapid curing at 60-80 ° C for 1-2 hours; if no further curing occurs, the possible reasons: the mixing ratio is not right or the main agent is not stirred evenly before mixing. If the main agent or curing agent reacts with other chemicals (such as solvents, strippers, greases or other incompletely cured base agents), this also affects the curing effect. After curing, it is only partially hard and leaves a very soft part; this can happen if the main agent and curing agent are not mixed evenly after mixing. Re-test, mix the main agent and the curing agent evenly to form a homogeneous mixture, then pour it into another cup and stir it for a while.
A customer asked me some time ago: Why do I sometimes have small bubbles sometimes appearing when I have a potting glue?
1. When stirring, due to the air entering, the air is not completely removed during the potting of the potting compound and the entire curing process, and small bubbles appear. In the case of such a problem, it is recommended that after the main agent and the curing agent are stirred together, the vacuum is applied or the potted product is also allowed to preheat during the potting of the product; Curing in a low humidity environment will allow enough time for the air to escape.
2. Because of the gas generated by the reaction of moisture and curing agent, large bubbles appear. In response to this problem, we first identify several possible causes of this problem:
(1) The main agent has been used many times, and moisture is mixed in each stirring process; it may also be because the lid of the package is not tightly closed. To prove what the cause is, mix the base and curing agent in a dry cup and dry in an oven (60-80 ° C) as described. If the bubble still occurs, the main agent has deteriorated at this time, please do not use it again.
(2) The potting product contains too much moisture. In case of such problems, it is recommended to re-test the product after preheating.
(3) The surface of the mixture of the main agent and the curing agent reacts with the moisture in the surrounding air. If this problem is encountered, it should be cured in a dry environment; if the product allows, it can be cured in an oven after heating.
(4) The liquid main agent and curing agent mixture may be exposed to other chemicals (such as solvents, release agents, varnishes, glues, etc.) before curing; such problems should be ensured to remove these substances before the next test. .
Next, explain some ways to change the performance of the main agent:
Curing time / operating time The operating time of most polyurethane potting compounds is 1-45 minutes. In some cases the maximum operating time may vary. But don't try to change the operation time by adding curing agent. Weifu can adjust the operation time. For manual operation, the operation time is about 45 minutes, and the curing time is about 4-24 hours. This time depends mainly on the main agent in the product. Type, temperature and amount of glue applied.
Viscosity Do not change the viscosity by adding more or less curing agent. Viscosity can be changed by:
(1) A low viscosity curing agent will lower the viscosity of the mixture, but this will also change the mechanical and thermal properties of the cured polyurethane.
(2) Weifu can increase the viscosity by adding a thixotropic agent, which also helps to improve the stability and thixotropy of the liquid base and curing agent mixture without changing its mechanical and thermal properties. Hardness Do not attempt to change the hardness by adding too much base or curing agent as this will have a negative impact on the mechanical properties of the cured polyurethane. The hardness can be slightly changed by using another type of curing agent. If you need another grade of hardness, use a different base.
Q：How many people are there in your company's R&D team?
A：Shenzhen Zhongfu Optoelectronics provides customers with a complete set of power solutions. We have been consistently paced. We have excellent quality, 30-50 engineers with excellent engineering team, and we will not fall to the production army, whether in the current market or the future market. Zhongfu Optoelectronics will continue to improve continuously and improve service quality, becoming the primary choice of the power industry, becoming a more powerful hammer for customers, and being your power partner for professional integrity.