Fwd: Re: [sdiy] VCA controls

[Don Tillman]

   > >From: "Happy Harry" <paia2720 at hotmail.com>
   > >
   > >Oh YEAH baby...
   > >
   > >LED VU meter...  use the LM3914 and let the nasty spikey noise
   > >get all over your power supply.... AND contribute to global
   > >warming at the same time.

   > Date: Fri, 10 May 2002 14:19:59 -0700
   > From: greg montalbano <greg.montalbano at ucop.edu>
   > 
   > I was wondering the same thing (in slightly less acerbic terms) --
   > have some of you come up with ways of including mass LEDs without
   > the associated monster current drain?

Use the LM3914 but put the LEDs in *series*, drive the top of the LED
string from a constant current source, and optionally add a zener
diode to keep the current constant for the case when all the LEDs are
off.

As Emeril Lagasse would say, "BAM!"

  -- Don

-- 
Don Tillman
Palo Alto, California, USA
don at till.com
http://www.till.com