Alt-BEAM Archive
Message #00518
To: beam@corp.sgi.com
From: Justin jaf60@student.canterbury.ac.nz
Date: Wed, 17 Feb 1999 20:02:13 +1300
Subject: [alt-beam] Re: 240-based 'reverser' query
Sean Rigter wrote:
>
> You are absolutely right Justin: this is not a good diagram
>
> 1. No doubling = less current is the price you pay for this reverser
> 2. Always use 74ACxxx for higher current (typ ~50mA per output)
> 3. The diagram is wrong: the bottom output/input labels are swapped
> 4. Missing connections everywhere!
> 5. Where did this diagram come from?
>
> Want me to correct it?
I decided to do that myself (gotta learn somehow :) and the resulting
diagram is open for criticism, but I believe it's correct:
http://www.geocities.com:80/SoHo/Lofts/1121/beam/240reverser.gif
For my purposes (reverser in a photovore) I'm thinking that a 74HC240
would seem the best choice as a) It draws (considerably?) less power to
run, b) it will use small, low-power motors anyway and c) I er... don't
think I can get the 74AC's here... :-)
Question - Can the 240's be stacked for higher current? (My assumption
is yes, but I thought I'd ask)
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