[sdiy] logic question

[Paul Maddox]

Alex,

> i was wondering how one goes about implementing a "if greater than X but
> less than Y" circuit.  i see a lot of circuits that will do X if greater
> than a certain voltage, but say i have three LEDs that i'm feeding
voltage,
> and these LEDs go on at 1v, 2v, and 3v respectively.  if i get to 2v, i
> don't want LED1 to still be on, and if i get to 3v, i don't want LEDs 1
and
> 2 to still be on.  how do i go about shutting off the first LEDs whent he
> voltage goes higher?

If you get one of the LMxxx Display driver chips (cant remember which now)
they have a BAR mode (which is what you describe as unwanted) and a DOT
mode which is what you do want.. its just a pin you select either 5v or 0v.

Paul
_______________________________________
Wavesynth home page;-
    Http://www.wavesynth.com
Modulus synthesizers home page;-
    Http://www.wavesynth.com/modulus