Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Calculating radiant power of LED over its whole spectrum

  1. Nov 3, 2012 #1
    Hello

    OK so I'm very new to electronics and I really need some clarification/guidance. I am using this integrating sphere which is basically just a glorified photodiode.

    I am going to be measuring the output photocurrent using the responsivity curve of the photodiode. The sphere also has a port for measuring the spectrum of the light source which in this case is an LED. Using a simple multimeter I can measure the photocurrent which lets say for example is 10uA.

    I can simultaneously measure the spectrum of the LED using a spectrometer from which I get the intensity in arbitrary units as a function of wavelength. Now I have the responsivity curve i.e. the responsivity as a function of wavelength of the photodiode detector but what I want to do is calculate the total radiant power over the whole spectrum of the LED.

    So do I find the power for each wavelength using the responsivity of the photodiode? so for example with a photocurrent of 10uA at a wavelength of 500nm which corresponds to responsivity of 0.6A/W I get 0.016mW radiant power

    So do I then at 505nm which corresponds to responsivity of 0.58A/W calculate 10u/0.58 = 0.017mW? i.e. can I use the same photocurrent when calculating the radiant power at each wavelength as long as I use the corresponding responsivity? and then can I just sum up all the powers at each wavelength to get the total radiant power over the whole spectrum of the LED?

    But do I also need to take into account the intensity vs wavelength spectrum measured as well?

    I'm so confused!!!
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted



Similar Discussions: Calculating radiant power of LED over its whole spectrum
  1. Battery Powered LED (Replies: 4)

Loading...