The radiant and luminous power spectra, efficiency, and luminous efficacy of commercially available light-emitting diodes (LEDs) are measured. The output radiant power is determined with a silicon photodiode from its typical spectral response. A calculation of the radiant power spectra and the luminous power spectra is demonstrated. The frequency response of the LEDs is determined in the range 10–107 Hz. For the white LED, the frequency response of the primary blue emission and the green-yellow phosphorescence is measured separately, and the phosphorescence time constant is estimated. The ratio h/e is estimated using the emission wavelengths and the “turn-on” voltages.
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PAPERS| August 01 2011
Experiments with light-emitting diodes
Yaakov Kraftmakher; Experiments with light-emitting diodes. Am. J. Phys. 1 August 2011; 79 (8): 825–830. https://doi.org/10.1119/1.3599072
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