How much power can you get out of an LED?

Discussion in 'General Electronics Chat' started by hp1729, Jan 13, 2016.

  1. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
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    Yes, if you shine a light on an LED it generates a voltage. How do you determine how much power you can get out? If I put a resistor in parallel with it of 100K ohms the voltage drops to almost zero volts. 1M I get about 0.2 V. 10 M I get 1.2 volts. No resistor I get 1.4 Volts.
    I am using an 8 mm diameter white LED.
    With the 10 M I calculate about 0.12 microamps at 1.2 V. So am I looking at about 0.144 microwatts? Not very efficient.
    If I use colored LEDs do I get color sensitive readings?
    Has anyone else played with this idea?
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    LEDs will never be efficient for photovoltaic power generation; collector area is too small.
     
  3. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
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    Agree!
     
  4. fiberstorejames

    New Member

    Aug 5, 2014
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    Agree with "collector area is too small".
     
  5. Johann

    Senior Member

    Nov 27, 2006
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    No harm in experimenting! That's what makes our hobby/profession interesting and that is how new things are often discovered. At least you know that the LED is in a ready package and might serve as an optic sensor in one of your projects!
     
  6. hp1729

    Thread Starter Well-Known Member

    Nov 23, 2015
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    Such was the objective, yes, thank you.
     
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    If you need a color sensor take a peek at a company called ams (ams.com), formerly TAOS. They make several light and or color sensors that are quite useful.

    The only drawback using their products is AFAIK they only come in surface mount packages. Welcome to 2016.
     
  8. Papabravo

    Expert

    Feb 24, 2006
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    I guess it might be more efficient than trying to harvest useable energy from the RF background. There we are talking femtowatts. A femtowatt is 1e-15 watts.
     
  9. KJ6EAD

    Senior Member

    Apr 30, 2011
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