diff options
Diffstat (limited to 'other/day2/workexperience.ms')
-rw-r--r-- | other/day2/workexperience.ms | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/other/day2/workexperience.ms b/other/day2/workexperience.ms new file mode 100644 index 0000000..29755b3 --- /dev/null +++ b/other/day2/workexperience.ms @@ -0,0 +1,46 @@ +.TL +Notes from work experience day 2 +.AU +Lucas Standen +.AI +30/5/24 +.NH 1 +The voltage over an LED +.NH 2 +The experiment +.LP +Continuing on from yesterdays study of The wavelength of LEDs and how it change as the current was +increased, today I have taken results showing how time effects the voltage across the LED. + +I would predict that the LED's voltage will fall over time as the temperature increases, which will +cause the die to "slow down" so to say, or stop behaving as once intended. + +My results were taken on a green LED with a 10mA current provided at 2.2V. A multimeter was used to +capture data from the LED, it takes 2000 readings and outputs them in a csv file (my results can be +found in results.csv). + +I found it took on average 45 seconds for the multimeter to take 2000 results. +The data was taken at 1 nplc (1 nplc = 1/50hz) + +.NH 2 +Results +.LP +As expected the voltage over the LED fell slightly over time, the graph of these results can be seen +bellow. +.PSPIC graph.ps +.LP +Another graph showing the first 450ms can be seen here, this relates to how our pulse mesurements +from yesterday +.PSPIC graph2.ps +.LP +As you can see, this is experiencing exponential decay, falling quickly at first and then levelling +out. This was about as expected. The voltage falls, as the LED is too hot, then it reaches closer +and closer to equilibrium, where the total thermal output is the same as the power input. +.NH 2 +Takeaways +.LP +From my data I can take away that LED's are definitely thermally limited, one can see this from +today's data and yesterdays data. I have found it interesting how the LED can heat up so slightly +and yet it still have an effect on the voltage input. One would suppose there is a formula to model +this decay in voltage. + |