The LED light tube provides monochromatic light with a large half-width. Since the energy gap of the semiconductor decreases with the rise of temperature, the peak wavelength emitted by it increases with the rise of temperature, that is, the spectral red shift, and the temperature coefficient is +2~3A/. The LED luminous brightness L is approximately proportional to the forward current. As the current increases, the luminous brightness also increases approximately. In addition, the luminous brightness is also related to the ambient temperature. When the ambient temperature is high, the recombination efficiency decreases and the luminous intensity decreases.　　1, look at the package and label 　　 the national mandatory product LED lighting manufacturer marked the following on the package: rated voltage range, rated power, rated frequency. In general, the printed high-quality products are of good quality, clear handwriting, not easy to fall off, wipe with a soft damp cloth, the logo is clear and identifiable, the manufacturer's trademark and related certification marks.　　2, look at the appearance of the LED tube 　　 real LED fluorescent lamp. From the perspective of the lamp, the shape and size of the lamp are better and more consistent, the product consistency is good, and the quality assurance is easier. Of course, there can be no cracks or looseness between the interfaces. The led tube must choose the kind of engineering plastic flame-retardant plastic PC shell. Ordinary plastic deformation and flammability, the aluminum tube must be bright, aviation aluminum.　　3. Working temperature　　 When the LED fluorescent lamp is in normal operation, the temperature should be low. Otherwise, the life span of the LED lamp is very short. At the same time, when the energy-saving lamp is lit, it flickers rapidly or fluctuates very harshly, indicating that the energy-saving lamp has a quality problem. After a few minutes of power-on, there should be a temperature, which proves that the heat dissipation is good, and the aluminum substrate used for heat dissipation. Without temperature, it is a fiberglass board, and the heat cannot be dissipated.　　4. Look at the start-up performance　　The start-up of the LED fluorescent lamp has a feature: it lights up when it is powered on, and does not flicker.　　5. Weigh, compare the weight with each other, the heavier is better than the lighter, and the heavier is better for the material.