[sdiy] logic question

[Happy Harry]

Easiest way would be to use the LM3914 bargraph driver chip,
and choose dot mode.

See also "Multiple Aperture Window Discriminator" from National
Semiconductor Ap note AN-31

And also AN-74 "Limit comparator with lamp driver"... this one uses
the outputs in "wire-or" so that the lamp would light only at the
2V setting you describe. Separate the comparator outputs and you can logic 
decode to get only one lamp at a time.

Helps ???

H^) harry


>From: Alex Dickey <Alex at centricitysoftware.com>
>To: "synth DIY (E-mail)" <synth-diy at node12b53.a2000.nl>
>Subject: [sdiy] logic question
>Date: Mon, 16 Apr 2001 09:51:09 -0700
>
>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?
>
>thanks,
>alex
>
>
>
>http://www.geocities.com/aurelialuz/
>
>"wha-na-na-na-na-na-na-na-na-na."
>-j. caletti
>

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