[sdiy] Speaking of LEDs...

[John L Marshall]

And, if the voltage is wagging (going positive then negative fast enough)
get colors between the two.


Take care,
John
www.sound-photo.com
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----- Original Message -----
From: "patchell" <patchell at silcom.com>
To: "Peter Grenader" <petergrenader at mksound.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, February 06, 2003 7:41 PM
Subject: Re: [sdiy] Speaking of LEDs...


>     There is no problem, the diode will always be forward biased, you just
need
> to make sure you don't exceed the maximum current.
>
>     But, here is a sugestion...if the voltage can go both positive and
negative
> about ground, use a two lead-bi color LED and tie it to ground instead
of -12.
> That way, when the voltage is positive, you will get one color, when
negative,
> another...
>
> 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
>
> --
>  -Jim
> ------------------------------------------------
> * Visit:http://www.silcom.com/~patchell/
> *-----------------------------------------------
> *I'm sure glad Merry Christmas comes just once a year
> * -Yogi Yorgensen
> ------------------------------------------------
>
>