H LV <hveeder...@gmail.com> wrote: In my question I said if you only had an LED. That implies a resistor is > not available. >
Well, in that case, you simply prevent any light from leaving the LED. Cover it with something. Then put it in a box with a very sensitive light meter to conform that nothing is escaping from it. You can generate heat from a mechanical device such a wind-up toy with similar methods. That is a classic 19th century experiment. I don't see how this would arise in the real world, but perhaps it might. Similar problems arose with the development of silicon integrated circuits. Silicon is not a good choice of materials for many cell components such as resistors. It had to be used, because it is a semiconductor, but it did not lend itself to that purpose. - Jed
