SED or Smoke Emitting Diode
2008-11-25 22:34
This is an attempt to record the very edge to which an LED can be driven. A failed attempt.
I tried to post this as a component page, but it would not take embedded video...
The LEDs I tried are rated at 30 mA maximum. The forward voltage is between 1.9 and 2.1 V. I used a power source of 8.1 V and a variable resistor in series that could range from 5000 to 0 Ohm.
I consider this experiment failed because I could not bring the LED to the brink of extinction (or rather ignition). It proved very difficult to bring the current through the LED to exactly 30 mA using nothing but a simple 5k linear potmeter. Once at 25 mA, it went straight up and off the scale. The difference in the angle of the potmeter was unnoticeable. I suggest someone takes this from my hands (and budget) and continues with a PWM signal generated by a micro controller. That should be much more manageable.
Great fun though!
8ik
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why not use a series
if you got 'm
Good grief, I am going to
Good grief, I am going to have to take a crack at this. Maybe after making my lab coat.
I have a TON of pots (all leftover from school x2 because there was a paperwork issue and I got two sets *g*). For some reason I still hold the notion that every component I have is precious and I should do all that I can to not destroy them for the sake of amusement.
Maybe if I perform a sacrifice of an LED my projects will go more smoothly?
Sacraficial Anode just took on a whole new meaning!
potmeter sucks
Spending way too many brain cells on this one. But I now know not to trust these potmeters with any job that requires them to work over the full range.
This is my 10 kΩ / 270° potmeter from the video, turned to an angle of almost 0°. This measures as 230 Ω. When I push it nearer to 0°, it jumps to zero Ω. I noticed the same behaviour in ten-turn pots as well. Maybe this experiment is why logaritmic potmeters were invented. Or fixed resistors in series!
8ik
Wire wound pots!
When you need low ohms and the ability to handle more than a few mA wire wound pots are the go. Basically resistance wire wound around an insulating former with the wiper draging across the turns. You can even do homemade versions for custom jobs.
Add a resistor to your circuit
All of the wirewound pots I
I understood 0% of this
warning
lol!
Maybe my next video will have a warning for artsies showing the first ten seconds.8-)