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Topic: Why do LEDs explode? (Read 1 time) previous topic - next topic

superKittens

This isn't so much a multiplexing question as it is chemistry.

It's no surprise that giving too much voltage to LEDs can make them explode.  However, does somebody know the chemistry behind why they explode?  I imagine it's due to the heat being generated by the increasing current which would break down some material in the LED causing them to go into a gaseous state.  Eventually the pressure builds so much that the LED explodes.  But...what exactly gets changed to gas?

I tried googling this, but it seems the internet is more interested in making LEDs (and caps) explode than explaining why they do so.

Thanks!

fungus


This isn't so much a multiplexing question as it is chemistry.


It's a form of multiplexing/visualization ... ideal for visualizing music like the 1812 overture (for example).

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

Aaron_dyer

I'm sure if you look at Cree on google.....( they are in Raleigh ) as am I, but they are the leading manufacturer for LEDs, it could help you. I had one do so on me too.....big POP sound. A lot of semiconductor elements inside there producing frequency......especially blue LEDs

Hippynerd

Im pretty sure that it has everything to do with the LEDs inability to disperse heat, that little plastic body holds the heat in too much. At some point the heat causes expansion, and the heat cant escape well, so the part breaks.

Tom Carpenter

As you try and force more and more electrons to flow through the diode (i.e. a higher current), more energy is dissipated in the semiconductor due to collisions between the electrons and the lattice structure of the semiconducter material. The heat causes the lattice to gain energy and expand.
The plastic doesn't expand as much and so pressure builds up inside the LED until the plastic fails and cracks at which point all the energy stored up pressing against the inside of the shell is rapidly dissipated in the form of pressure waves (sound) and kinetic energy (the bits of plastic launching across the room).

Granted that is a catestrophic failure. In many cases the failure will not be catestrophic, but rather simply the fragile metal wire interconnects will melt rather like a fuse does. Though either way the final outcome is the same... you have to buy a new LED  :).
~Tom~

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