Experiments with Fluorescent Lamps

Kraftmakher, Yaakov

doi:10.1119/1.3488190

Cited by 6 publications

(4 citation statements)

References 9 publications

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“…A significant disadvantage of fluorescent lamps is the use of mercury, a harmful source of environmental pollution. For student experiments with fluorescent lamps, see [7][8][9] and references therein.…”

Section: Fluorescent Lightingmentioning

confidence: 99%

Nobel Prize for blue LEDs

Kraftmakher

2015

Eur. J. Phys.

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A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and 'efficiency droop' in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

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Section: Fluorescent Lightingmentioning

confidence: 99%

Nobel Prize for blue LEDs

Kraftmakher

2015

Eur. J. Phys.

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“…The same setup, but with a grating of 600 lines per millimetre, is used for comparing spectra of two compact fluorescent lamps (CFL) tested in our previous experiments [4]. The manufacturers characterize them as a 'cool daylight' lamp and a 'warm white' lamp.…”

Section: Radiant Spectra On the Oscilloscope Screenmentioning

confidence: 99%

“…The mercury line at 546 nm and the phosphor emission form the intensive green band necessary for obtaining high luminous efficacy of a lighting source (see, e.g. [4,5]).…”

Section: Radiant Spectra On the Oscilloscope Screenmentioning

confidence: 99%

Demonstrations of optical spectra with a video camera

Kraftmakher¹

2012

Phys. Educ.

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The use of a video camera may markedly improve demonstrations of optical spectra. First, the output electrical signal from the camera, which provides full information about a picture to be transmitted, can be used for observing the radiant power spectrum on the screen of a common oscilloscope. Second, increasing the magnification by the camera enhances the resolution of the spectra displayed by a colour monitor. In particular, it becomes possible to resolve the sodium doublet at 579 nm ( λ = 0.6 nm).

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“…21). The color temperature does not mean that the spectrum of a light source is similar to that of a blackbody of equal temperature.…”

Section: The Setupmentioning

confidence: 99%

Experiments with light-emitting diodes

Kraftmakher

2011

American Journal of Physics

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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 10-10 7 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 "turnon" voltages.

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Experiments with Fluorescent Lamps

Cited by 6 publications

References 9 publications

Nobel Prize for blue LEDs

Nobel Prize for blue LEDs

Demonstrations of optical spectra with a video camera

Experiments with light-emitting diodes

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