Tungsten filament lamp is an incandescent lamp made with tungsten filament as the filament. Tungsten filament lamp can produce continuous spectrum, which can be used in 400~780nm visible spectrum area. Used as a visible light source in a spectrophotometer. Its spectral effective region can extend to 3 μ m. Therefore, it is also used as a light source in the near-infrared region.
An electric light source that emits light through an electric current using tungsten wire in a vacuum (filled with inert gas).
To increase the service life of the light bulb, the length of the tungsten wire can be extended. Allowing thermal energy to be distributed over a longer space will lower the temperature of the filament, naturally reducing sublimation and extending the lifespan of the bulb. But because the temperature has also decreased, the efficiency of producing visible light has also decreased. The light bulb becomes darker and requires a higher power bulb to produce the same brightness.
Although increasing the lifespan of the light bulb saves some money, it is worth considering whether the wasted electrical energy is worth it. Therefore, long life bulbs are usually more cost-effective to use in places where it is difficult to replace bulbs. If the length of the filament is made longer, the temperature is lower, and even a faint dim red light is emitted, the heat (infrared) emitted can still be clearly felt.
In addition, for the flash used in early photography, in order to generate a spectrum closer to sunlight, the filament length was shortened to work at higher temperatures, resulting in a shortened working life of several hours. (The gas added to the filament causes the generated spectrum to be equivalent to the spectrum of a blackbody at approximately 4500 ℃ - higher than the filament temperature)
Advantages: Incandescent lamps have low power, low power consumption, and are also very cheap; It has various forms such as orientation, scattering, diffusion, etc; It has a good lighting effect. Wide versatility and a wide variety of color options;
Disadvantages: Incandescent lamps have a short lifespan, and compared to other energy-saving lamps, fluorescent lamps consume one-fourth of the electricity consumption of incandescent lamps at the same brightness. With the emergence of various energy-saving lamps, the power consumption of incandescent lamps has become even greater.