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Thread: Why do led lamps have a full spectrum while hydrogen lamps do not?

  1. #1 Why do led lamps have a full spectrum while hydrogen lamps do not? 
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    Does it have anything to do with hydrogen lamps being gas lamps?


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    Quote Originally Posted by whiplash504 View Post
    Does it have anything to do with hydrogen lamps being gas lamps?
    LED lamps fundamentally are narrow-spectrum emitters, just like gas discharge lamps. Phosphors are added to LED bulbs to broaden their spectrum, in precisely the same manner as in fluorescent lights. These work by a two-step process. The LED or fluorescent light first generates a short wavelength output (usually blue in the LED case, and UV in the fluorescent case), which then excites a phosphor coating, which then emits a whitish, broad-spectrum light. It's amazing that the overall efficiencies are as good as they are, given the potential inefficiencies in each step.


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    Led lamps don't have a full spectrum. Only filament lamps do. Just get a random CD-rom and check how the light is broken from it. A lightbulb will have a beautiful continues spectrum. LED-lamps will have 3 lines, as they are essentially 3 coloured leds mixed together. There is no such thing as a white light LED.
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    Hydrogen's only got one electron.

    Search_Niel's Bohr.
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    Quote Originally Posted by Geo View Post
    Hydrogen's only got one electron.

    Search_Niel's Bohr.
    That has absolutely nothing to do with it. First of all, yes Hydrogen has 1 electron. But hydrogen gas lamps do not have just H, this is a non stable gas. H2 is hydrogen gas. A small amount is ionized for the gas to become conductive. Then power is conducted via the gas and this exited both the hydrogen gas, as the ionized hydrogen gas. This means that radiation comes from energy levels of 2 different molecule's. The 2 electrons about 2 nuclei. And a small portion of 1 electron around 2 nuclei. This produces a set of discrete energies which has several frequencies. It is not a perfect spectrum but far more various then for instance LED, Which has a very small spectrum due to its nature and broadening to deficits in the structure.
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