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L. ight. E. mitting. D. iode. History. …Introduced as a practical electronic component in 1962. …Invented by Nick Holonyak Jr. while working in a GE laboratory in Syracuse, NY. …Initial LEDs only emitted a low-intensity red light. History. 1962. 1993. 1972. GaN. 1987. 1971.

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  1. L ight E mitting D iode

  2. History …Introduced as a practical electronic component in 1962 …Invented by Nick Holonyak Jr. while working in a GE laboratory in Syracuse, NY …Initial LEDs only emitted a low-intensity red light

  3. History 1962 1993 1972 GaN 1987 1971

  4. Current Applications Displays & Indicators for Electronics

  5. Current Applications Remote Controls, motion detectors, & optical sensors

  6. Current Applications Large format video displays & light sources for projection

  7. Current Applications Current Applications LIGHTING!

  8. Current Applications Current Applications

  9. Current Applications Current Applications

  10. = Advantages Low Power Consumption

  11. = Advantages Longer Life

  12. 460 120 Advantages Lower Heat Output

  13. Advantages On / Off Time Color Intensity Shock Resistance Toxicity Focusing

  14. advantages Dis Higher Initial Cost (Lower Energy & Maintenance cost)

  15. Disadvantages Not a spherical light source

  16. Disadvantages Poor natural reproduction of white light

  17. Disadvantages Multiple source shadow effect b = ( a x L2 ) / L1 a = LED spacing b = Shadow spacing L1 = Distance between LED & object L2 = Distance between object & surface

  18. Disadvantages Video Flicker LEDs utilize PWM (Pulse Width Modulation) for dimming The frequency of the PWM is not visible with the human eye, but is captured and emphasized in video

  19. Disadvantages Video Flicker Higher end LED lights use a much higher frequency PWM for dimming This allows the light to cycle faster than the video refresh, making the flicker virtually invisible on video

  20. Questions?

  21. Thank You!

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