Who can talk about the difference between the wick XML of LED flashlight and the previous one?

The XML series was recently launched by CREE Company of the United States, and was nicknamed "Little Donkey" by LED users. It is characterized by high brightness (XML-T6 can reach 860 lumens), high power consumption (full power driving current of XML-T6 is 3A), low forward turn-on voltage and high luminous efficiency. Pay attention to battery capacity, contact resistance and heat dissipation during normal use.

The LED used in flashlights by Kerui Company can be roughly divided into: P series, Q series, R series and XML series. Each generation is getting better, and P series is almost eliminated. The early Q series was a large nucleus, and later it was changed to a small nucleus. The main difference between Q series and R series is that the former has lower light efficiency, higher forward turn-on voltage and better long-range emission performance, while the latter has better light efficiency.

Personally, I think XML series is just a product of CREE's market segment. On the basis of R series, the brightness is improved by increasing the luminous core area and high current and power. In fact, as far as material technology is concerned, there is no big breakthrough, and its light efficiency is not too high when it is fully loaded.

When electrons recombine with holes, they can emit visible light, so they can be used to make light-emitting diodes. Used as an indicator light in circuits and instruments, or as a text or digital display. Gallium arsenide diodes emit red light, gallium phosphide diodes emit green light, silicon carbide diodes emit yellow light and gallium nitride diodes emit blue light. Because of its chemical properties, it can be divided into organic light-emitting diode and inorganic light-emitting diode LED.

It is a semiconductor diode, which can convert electric energy into light energy. Light-emitting diodes, like ordinary diodes, are composed of PN junctions and also have unilateral conductivity. When a DC voltage is applied to the LED, holes injected from the P region to the N region and electrons injected from the N region to the P region recombine with the electrons in the N region and the P region within a few microns near the PN junction, respectively, resulting in spontaneous fluorescence. The energy states of electrons and holes in different semiconductor materials are different. When electrons and holes recombine, the energy released is somewhat different. The more energy is released, the shorter the wavelength of light is. Diodes that emit red, green or yellow light are commonly used. The reverse breakdown voltage of LED is greater than 5 volts. Its forward volt-ampere characteristic curve is very steep, and a current limiting resistor needs to be connected in series to control the current through the diode. The current limiting resistance r can be calculated by the following formula:

R=(E-UF)/IF

Where E is the power supply voltage, UF is the forward voltage drop of LED, and IF is the normal working current of LED. The core of LED is a chip composed of P-type semiconductor and N-type semiconductor. There is a transition layer between p-type semiconductor and n-type semiconductor, which is called PN junction. In the PN junction of some semiconductor materials, when the injected minority carriers recombine with the majority carriers, the excess energy will be released in the form of light, thus directly converting electric energy into light energy. When reverse voltage is applied to PN junction, minority carriers are difficult to inject, so they do not emit light. This kind of diode made by injection electroluminescence principle is called light emitting diode, commonly known as led. When working in the forward direction (that is, DC voltage is applied at both ends), when the current flows from the anode of the LED to the cathode, the semiconductor crystal emits different colors of light from ultraviolet to infrared, and the intensity of light is related to the current.