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.
REFERENCES
1.
M. G.
Craford
and F. M.
Steranka
, “Light-emitting diodes,”
in Encyclopedia of Applied Physics
, edited by G. L.
Trigg
(VCH
, Weinheim
, 1994
), Vol. 8
, pp. 485
–514
.2.
B. G.
Streetman
and S.
Banerjee
, Solid State Electronic Devices
, 5th ed. (Prentice Hall
, Upper Saddle River, NJ
, 2000
), pp. 379
–396
.3.
S. M.
Sze
and K. K.
Ng
, Physics of Semiconductor Devices
, 3rd ed. (Wiley
, Hoboken, NJ
, 2007
), pp. 601
–621
.4.
N.
Holonyak
, “Is the light emitting diode (LED) an ultimate lamp?”
Am. J. Phys.
68
, 864
–866
(2000
).5.
S. K.
Mayer
, “Bringing science policy into the optics classroom: Solid state lighting and United States lighting standards,”
Am. J. Phys.
78
, 1258
–1264
(2010
).6.
H.
Kogelnik
, “Optical communications,”
in Encyclopedia of Applied Physics
, edited by G. L.
Trigg
(VCH
, Weinheim
, 1995
), Vol. 12
, pp. 119
–155
.7.
J. B.
Kwasnoski
, “A laboratory investigation of light-emitting diodes,”
Am. J. Phys.
40
, 588
–591
(1972
).8.
J. A.
Davis
and M. W.
Mueller
, “Temperature dependence of the emission from red and green light emitting diodes,”
Am. J. Phys.
45
, 770
–771
(1977
).9.
J. W.
Jewett
, “Get the LED out,”
Phys. Teach.
29
, 530
–534
(1991
).10.
D. A.
Johnson
, “Demonstrating the light-emitting diode,”
Am. J. Phys.
63
, 761
–762
(1995
).11.
D.
Lottis
and H.
Jaeger
, “LEDs in physics demos: A handful of examples,”
Phys. Teach.
34
, 144
–146
(1996
).12.
A. M.
Ojeda
, E.
Redondo
, G.
González Díaz
, and I.
Mártil
, “Analysis of light-emission processes in light-emitting diodes and semiconductor lasers,”
Eur. J. Phys.
18
, 63
–67
(1997
).13.
E.
Redondo
, A.
Ojeda
, G.
González Díaz
, and I.
Mártil
, “A laboratory experiment with blue light-emitting diodes,”
Am. J. Phys.
65
, 371
–376
(1997
).14.
L. T.
Escalada
, N. S.
Rabello
, and D. A.
Zollman
, “Student explorations of quantum effects in LEDs and luminescent devices,”
Phys. Teach.
42
, 173
–179
(2004
).15.
J. W.
Precker
, “Simple experimental verification of the relation between the band-gap energy and the energy of photons emitted by LEDs,”
Eur. J. Phys
. 28
, 493
–500
(2007
).16.
F. B.
Seeley
, A.
Bandas
, M.
Fowler
, and R.
Gibson
, “An inexpensive light-emitting diode strobe system for measuring the radius of a single sonoluminescing bubble,”
Am. J. Phys.
67
, 162
–164
(1999
).17.
P. A.
DeYoung
and B.
Mulder
, “Studying collisions in the general physics laboratory with quadrature light emitting diode sensors,”
Am. J. Phys.
70
, 1226
–1230
(2002
).18.
Se-yuen
Mak
, “A multipurpose LED light source for optics experiments,”
Phys. Teach.
42
, 550
–552
(2004
).19.
W. P.
Garver
, “The photoelectric effect using LEDs as light sources,”
Phys. Teach.
44
, 272
–275
(2006
).20.
HuiYuan Opto-Electronic <www.hyledchina.com>.
21.
Y.
Kraftmakher
, “Experiments with fluorescent lamps,”
Phys. Teach.
48
, 461
–464
(2010
).22.
PASCO <www.pasco.com>.
23.
Y.
Kraftmakher
, “Determination of the quantum efficiency of a light detector,”
Eur. J. Phys.
29
, 681
–687
(2008
).24.
Y.
Kraftmakher
, “Decay time of cathodoluminescence,”
Phys. Educ.
44
, 43
–47
(2009
).25.
OriginLab <www.originlab.com>.
26.
D. C.
Agrawal
, H. S.
Leff
, and V. J.
Menon
, “Efficiency and efficacy of incandescent lamps,”
Am. J. Phys.
64
, 649
–654
(1996
).28.
Y.
Kraftmakher
, “Telemetry in the classroom,”
Phys. Teach.
41
, 544
–545
(2003
).29.
Y.
Kraftmakher
, “Video through a light guide,”
Am. J. Phys.
76
, 788
–791
(2008
).30.
H.
Le Minh
, D.
O’Brien
, G.
Faulkner
, L.
Zeng
, K.
Lee
, D.
Jung
, and Y.
Oh
, “High-speed visible light communications using multiple-resonant equalization,”
IEEE Photonics Technol. Lett.
20
, 1243
–1245
(2008
).31.
P. J.
O’Connor
and L. R.
O’Connor
, “Measuring Planck’s constant using a light emitting diode,”
Phys. Teach.
12
, 423
–425
(1974
).32.
L.
Nieves
, G.
Spavieri
, B.
Fernandez
, and R. A.
Guevara
, “Measuring the Planck constant with LEDs,”
Phys. Teach.
35
, 108
–109
(1997
).33.
F.
Zhou
and T.
Cloninger
, “Computer-based experiment for determining Planck’s constant using LEDs,”
Phys. Teach.
46
, 413
–415
(2008
).34.
D. F.
Holcomb
, “LEDs: Their charm and pitfalls,”
Phys. Teach.
35
, 198
(1997
).35.
R.
Morehouse
, “Answer to Question #53. Measuring Planck’s constant by means of an LED,”
Am. J. Phys.
66
, 12
(1998
).© 2011 American Association of Physics Teachers.
2011
American Association of Physics Teachers
AAPT members receive access to the American Journal of Physics and The Physics Teacher as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.