[sdiy] Speaking of LEDs...

[Tim Ressel]

Peter,

Perhaps I don't understand your concern. I get about
9mA when I calculate the current, which in the range
for an LED. Your schematic shows 1K not 2K, which
gives about 18.3mA. Still Ok.  

--Tim

--- Peter Grenader <petergrenader at mksound.com> 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
> 
> 
> 


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