SED or Smoke Emitting Diode
November 25, 2008
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!