Saturday, December 03, 2011
Powered by led's
I do like led's but aside the fact they are nice to show power on in circuits I only did some minor tests with them. One of the experiments some time ago was to use a led as a poor and small replacement for a solar cell, yes led's can generate small amounts of energy. Some can sense radiation and other types of PN junction can be nice for temperature sensing (like 1n4148 diode)... normaly components have more than one function you know?! The classic example is a resistor used as a camera flash :) One time action of course!
Next images you have an infrared led, (I think, since I don't remember the specs or even when it was bought) the outer case is light blue and emits no visible light when direct biased.
Here in reverse connection getting some direct sun light.
Two of them in series should give 1.4V althoug on a very small current, this multimeter has 10M of internal impedance but if you put some in parallel you end up with a very small power supply as long as the sun shines...
Here's the "power" from a white color paint!:
Incidently this gave me the idea of using one of this for a very crude Sun photometer.... maybe one of this days...
And in the dark:
This led was the best one I tested, other standard types gave worst results.