**Re: what happens to LED\'s during thermal runaway**

Actually, thermal runaway is a complex phenomenon, because resistance *increases* as temperature does.

(Remember that supercooling leads to virtually no resistance, hence, superheating leads to higher resistance.)

Thermal runaway is simply the inability of a material to dissipate its own heat. Heat is directly proportional to power, which is resistance times current squared.

At small currents, temperature is not a factor at all.

At moderate currents, as current increases ever so slightly, temperature increases slightly, increasing resistance by a similar amount, which in turn reduces the current again. Here, the system operates in a steady state, and power is constant.

But beyond a critical value of current, the square of the current starts to dominate the increased resistance. The additional resistance no longer can lower the current, so the temperature can no longer go down.

The material continues to absorb power it can no longer dissipate, so its temperature starts to increase rapidly. It's now just a matter of time before the material destroys itself.