PHY 4822: determination of h with
LEDs
-
What you have to do:
- measure room temparature with the thermometer available in the lab
-- compare with temperature reading of the LED apparatus
- do measurements for at least two LEDs
- for every LED, obtain I-V and I-T characteristic
(see users' manual below)
- repeat the I-T characteristic for a slightly different voltage -- discuss
your findings
- do realistic uncertainty estimates for the directly measured quantities
(justify your assumptions), and assess how this influences the uncertainty of
η and h;
- in particular, determine and quote uncertainties of slopes obtained from
I-V and I-T data
- in your write-up, explain the diode equation (where does it come from,
meaning of variables, physics background)
- quote your values (and uncertainties) for the material constant η
- explain the material constant η -- what is its significance?
What value do you expect for it? Is the value that you obtained within the
expected range? What value would it have in an ideal diode?
- your write-up should also have an explanation of how LEDs work
-
manufacturer information:
-
LED specifications (wavelength of emitted light):
- 458 nm Blue
- 563 nm Green
- 583 nm Yellow
- 660 nm Red
About LEDs: