Xref: utzoo sci.electronics:15258 comp.sys.ibm.pc.hardware:2637
Path: utzoo!utgpu!cunews!bnrgate!bwdls58!mlord
From: mlord@bwdls58.bnr.ca (Mark Lord)
Newsgroups: sci.electronics,comp.sys.ibm.pc.hardware
Subject: Re: Simple one evening project
Keywords: IBM, PC, floppy drive, LED, in use, color, density
Message-ID: <4749@bwdls58.UUCP>
Date: 29 Oct 90 15:51:53 GMT
References: <1990Oct23.162706.10585@elroy.jpl.nasa.gov< <4748@bwdls58.UUCP>
Sender: mlord@bwdls58.UUCP
Reply-To: mlord@bwdls58.bnr.ca (Mark Lord)
Organization: Bell-Northern Research, Ottawa, Canada
Lines: 28

In article <4748@bwdls58.UUCP> I wrote:
>
>Well, Radio Shack (here) only sells the two-lead type of bicolor LEDs.
>With these, the direction of current flow determines the LED color.
>
>Any gurus out there who'd be willing to post an equally quick&clean 
>circuit for performing the same function with this two-lead type of LED ?

As a starter, I propose the following circuit, using a quad NOR gate package:
                              |\
 Reduced Write -+-------------| \o------+
               -|--       +---| /       |
               \  /       |   |/       LED
                \/        |             |
                 o        |   |\        R220
                 +--------|---| \o------+
 ____________             |   | /      
 Drive In Use  -----------+---|/     


The invertor from ReducedWrite to the bottom NOR gate is simply
one of the spare NOR gates from the package, with the other input 
tied to ground (resistor?).
-- 
 ___Mark S. Lord__________________________________________
| ..uunet!bnrgate!mlord%bmerh724 | Climb Free Or Die (NH) |
| MLORD@BNR.CA   Ottawa, Ontario | Personal views only.   |
|________________________________|________________________|