Date   : Sat, 11 Feb 2006 11:15:35 -0000
From   : "David Hunt" <dm.hunt@...>
Subject: Re: BBC B+ LED problem

> > very seldom die, most LED deaths are caused by overheating with a
> soldering
> > iron or being over driven. Likely to be a dry solder joint, especially
> if a
> 
> I read that as "being driven over" :o
> 
> --
> J.G.Harston - jgh@... - mdfs.net/User/JGH
> There are three food groups: brown, green and ice cream.

"Over driven" a la Spinal Tap's Marshall amps, someones turned it up to 11.
Put 150mA through a 80mA ultra bright blue LED and the colour changes from a
blue to a purple, briefly white and then ohmigod I have a black light LED
and it even works when I remove the power! ;)

If you put too much current through an LED you tend to get a richer and
brighter colour at the expense of power consumption and LED life expectancy.

e.g. <http://www.gilbertinc.com/leduse.htm>

I can't see how this could happen in a Beeb though, unless someone thought
the LEDs were too dim and removed the current limiting resistors...

Dave ;)