[sdiy] Speaking of LEDs...

[Scott Bernardi]

LED's really respond to current in the forward direction, not voltage, so as
long as you have enough series resistance to limit the current to 20mA-30mA or
less you can put 100v across it. It's in the reverse bias direction that you
have to worry about zenering. You should be fine with 20v reverse bias too.

Peter Grenader wrote:

> Question for the masters:
>
> How lame is it that I am driving an LED with 20 volts across it and a 2k
> current limit?
>
> We thinks that before too long, it will be blown to smitherens and become a
> zener. I was thinking of putting a few 1N4148's in there in series with it
> to lessen its load.
>
> What I want to do is a cheap and dirty way to show the level of a smooth
> random voltage, which will fluctuate between these two rails (about +8 volts
> to -12).  I am currently driving this with a unity gain op amp.
>
> to see the specific application, go here:
>
> http://www.buzzclick-music.com/sample_hold.jpg
>
> Any suggestions?  OK the way it is?
>
> thanks in advance,
>
> Peter