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IR Leds or Visible ?

Discussion in 'LEDs and Optoelectronics' started by colum, Jan 22, 2015.

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  1. colum

    colum

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    Jul 25, 2013
    I want to run about 75 ft of Fiber Optic cable as an ON Off type of switch.. All of the LEDs that I have are IR, so my question is...Is IR better for long transmission and receiving or is visual Leds better since the activating light can be adjusted in intensity.
    Would it be better to use an adjustable visible light source and an IR receiver as they seem fairly sensitive to both

    Anyway visible light receivers are a little hard to find

    Thank you for reading this
    colum
     
  2. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    For glass fibre cables it is better to use IR because of it's greater wave length. This gives less attenuation versus visible light.
    Thanks
    Adam
     
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  3. Gryd3

    Gryd3

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    Jun 25, 2014
    You can indeed adjust the intensity of an IR LED just like any other LED.
    You can use most digital camera view finders to detect the output from the IR LED.

    Please note that commercial fiber uses quite intense IR, please practice safe handling of fiber and never look into the end of an optical fiber! Just because you can't see IR does not mean it's not there.
     
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  4. colum

    colum

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    Jul 25, 2013
    thanks Adam that explains it...colum
     
  5. colum

    colum

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    Jul 25, 2013
    Thanks Gryd3 for that very very good safety advice and advice on use of a digital camera
     
  6. colum

    colum

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    Jul 25, 2013
    i was under the impression that an Led light brightness could not be adjusted, if it called for a 300 ohm resistor at 12v that's what it needed
    Thanks for your advice...colum
     
  7. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Hi Colum
    You can adjust the light output of an LED from nothing to it's maximum rating by changing the current. The life of the LED is also effected by current, but even at maximum current they still last a very long time. You can also pulse them at current greater than the maximum but you would have to consult the data sheet for that information.
    Adam
     
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  8. colum

    colum

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    Jul 25, 2013
    Thanks Adam for your reply, that clears that up, Be well....colum
     
  9. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    And you mate!
     
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