Classification of lighting
The lights commonly used in home can be roughly divided into three categories:
Incandescent lamp: it is a lamp that relies on tungsten filament to emit light. The lamp invented by Edison usually emits warm yellow light with low color temperature; The heating is serious, so the luminous efficiency is low. The power of the same brightness is much larger than that of fluorescent lamps, LEDs, etc., and has been basically eliminated. The reason why it is basically eliminated is that it is generally not used. It is also used occasionally to set off the atmosphere. Although it costs much electricity, it is much better than candles, and it has a retro feeling. Of course, there are many LED lights made of incandescent light. It looks like they also have filaments, but a closer look shows that the filaments are very thick. In fact, LED light emitting materials at that time were not ordinary incandescent lights. Of course, it does not mean that incandescent lamps are useless. They are convenient for dimming, and can adjust the brightness by changing the voltage, current or series resistance.
Fluorescent lamp (fluorescent lamp, energy-saving lamp): This kind of lamp uses ultraviolet ray to irradiate fluorescent agent to emit fluorescence. Of course, different fluorescent agents can also be used to emit light of different colors. Compared with incandescent lamps, fluorescent lamps have stronger light color rendering, higher luminous efficiency, larger luminous area and better lighting effect. The disadvantage is that its structure is more complex, requiring a ballast, and the brightness cannot be adjusted simply by adjusting the voltage or connecting the resistance in series.

LED lamp: LED is a light emitting diode, which relies on semiconductor materials to emit light. Of course, it can emit light of different colors. Its luminous efficiency is very high, and its size is small (the headlamp is generally composed of multiple LED beads). It can be made into different styles, which is very flexible and convenient. The disadvantage is that the current domestic standard for LED lighting is not clear enough. There are many low-end products on the market with poor lighting effect, uneven spectrum, and long-term use may even damage the eyes. At the same time, LED is generally driven by constant current, which requires a special driver and a special dimming circuit. It cannot be dimmed simply by changing the voltage or connecting the resistance in series.