Police Flashlight using a xenon lamp or bright led xenon lamp HID is the abbreviation HighintensityDischarge high-pressure gas discharge lamp , known as heavy metal lamp or xenon lamp . Its principle is in the UV-cut anti - UV crystal quartz glass tube filled with a variety of chemical gases , most of which is an inert gas such as xenon (Xenon) and iodide , and then the DC through the turbocharger (Ballast) instantaneous voltage booster to 23,000 volts , after high amplitude excitation of the xenon electronic free quartz tube , between the two electrodes to produce light , which is the so-called gas discharge

White super xenon arc light , can improve the light color temperature similar to daylight sun light .

LED (Light EmittingDiode), light emitting diode, is a solid state semiconductor devices , which can be converted directly into electricity for light .

The heart of the LED is a semiconductor chip , the chip attached to one end on a bracket , one end is negative , the other end to connect the positive power supply so that the whole chip to be epoxy encapsulated .The semiconductor chip consists of two parts , the part of the P-type semiconductor , the dominant hole in it , the other end of the N-type semiconductor , here is mainly electronic .But the two semiconductor connected when they form a "PN junction ". When the current through the wire to the chip , the electrons would be pushed to the P region in the P region electron -hole recombination , and then will be issued in the form of photon energy , which is the principle of LED light . The wavelength of light is the color of light is determined by the material to form a PN junction.