I haven't the time to give you an answer but I tell you what I will do for
you . I will pass this posting onto my 12 year old nephew with a few
components and some test equipment and see what answer he comes up with for
you. I'm sure he will be able to come up with something over the weekend in
between doing his homework from school.

Chris Carr

> Hi again,
>
> Thank you for your replies to my question thus far. Advise me on the
> following by choosing the most correct answer. I think it is [2] or [3].
>
> If I have two LEDs that are radiating each other from a distance of
approx.
> 1mm and both are driven by current sources, then:
> 1. The diodes will become unstable
> 2. Electrical power to diodes will increase
> 3. Voltage across diodes will increase
> 4. Light output of both diodes will increase
> 5. Light output of both diodes will decrease
>
> Thanks.
>
> Regards,
>
> S. Sinha (Saurabh)
> Tel/Fax: (012) 343-4912
> Cell: 0825405577
> E.Mail: ssinha@IEEE.ORG
> Visit: http://home.mweb.co.za/si/sinha [Home]
> Visit: http://ieee.up.ac.za/members/saurabhs [Work] [Underconstruction]
> WAP site (Access a small version of mysite thru' ur cell):
> http://mobile.worldonline.co.za ID:1011 [Underconstruction]
> ICQ: 82010326
>
> ----- Original Message -----
> From: "Spehro Pefhany" <speff@INTERLOG.COM>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Wednesday, June 06, 2001 2:07 PM
> Subject: Re: [EE]: LED as a photodiode- theory
>
>
> > At 11:57 AM 6/6/01 +0200, you wrote:
> > >Hi,
> > >
> > >Here's a theory question:
> > >
> > >Can a LED be used as a photodiode?
> >
> > Sure. Here's a quick test. 7.25mA through a 3mm super-bright
> > LED nose-to-nose with a second similar LED with a 1M resistor
> > across it gives a photovoltaic voltage of 0.53VDC.
> >
> > Reverse biased, same setup as above 0.714V (on) into a 1M load
> > with 21.7V reverse bias (way over the 5V rated), 0.000V with
> > source LED off.
> >
> > As always, in production situations you may be better off using
> > a characterized part.. blah blah.
> >
> > Best regards,
> >
>
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> =
> > Spehro Pefhany --"it's the network..."            "The Journey is the
> reward"
> > speff@interlog.com             Info for manufacturers:
> http://www.trexon.com
> > Embedded software/hardware/analog  Info for designers:
> http://www.speff.com
> > Contributions invited->The AVR-gcc FAQ is at:
> http://www.bluecollarlinux.com
> >
>
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
> =
> >
> > --
> > http://www.piclist.com hint: PICList Posts must start with ONE topic:
> > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
> >
> >
> >
>
> --
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>
>
>

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