1. Constant current, non-flicker-free LED voltage is determined by the chip itself, but the resistance will change with the increase of temperature, if the constant current power supply is not used, the current of the LED will increase, and it will work if it exceeds the rated current for a long time. Greatly shorten the service life of the LED. And LED constant current is to ensure that its operating current remains unchanged when environmental factors such as temperature and voltage change. And constant current can make the lamps without flicker. 2. Input voltage You can see that the input voltage of some light tubes is wide, generally 85v-265v/AC. This kind of power supply will play its role when the voltage fluctuates greatly-it will not follow the fluctuation of the voltage. Affect the brightness. 3. Isolated power supply and non-isolated power supply are safe, and the price will be relatively high; non-isolated power supply is not as safe as isolated power supply, but safety measures should be taken in all aspects. The cost performance is very high, especially in efficiency. And the power factor, the advantages are more significant! RC and high-voltage ic power supply are cheap, but they will produce flicker, and the safety is relatively low.　　4, power efficiency, power factor 　　 output power (output LED voltage * output current) / input power. This parameter is particularly important. If the efficiency is low, it means that a large part of the input power is converted into heat and emitted; if it is installed in a light tube, a very high temperature will be generated, and the LED chip will also generate heat. It will superimpose to produce higher temperature, and the life of all electronic parts in our power supply will be shortened with the rise of temperature. Therefore, efficiency is also the fundamental factor that determines the life of the power supply. The efficiency cannot be too low, otherwise the heat consumed on the power supply will be too large. . The power factor is numerically, the power factor is the ratio of the active power and the apparent power, that is, cosΦ=P/S. A low power factor will generate a large amount of reactive power, which will affect the efficiency of the power grid and also cause interference to the power grid. The requirements for engineering and factories will be higher! Generally, the efficiency is above 80 and the power factor is above 0.8.　　5. Brightness, lifespan 　　 At present, the luminous efficiency of the LED tube is 90-100lm/W, and the lifespan is more than 20,000 hours. You need to pay attention to the chip and power supply used!