Alt-BEAM Archive
Message #00063
To: richfile@rconnect.com
From: Benjamin Edward Hitchcock beh01@uow.edu.au
Date: Mon, 1 Feb 1999 11:59:25 +1100 (EST)
Subject: [alt-beam] Re: New (feasible) photovore circuit?
Ahh, that's because they're not really diodes at all, but crude
photodiodes (wink wink, nudge nudge!)
Leds develop a voltage across them when exposed to light. It's the
voltage that I use, and there is almost no current - so the reverse
biasing effect doesn't come into play.
So if you have two similar photodiodes, each generating almost the same
voltage, then if you put them nose to nose, then you will only see the
difference in voltage levels, won't you?
That's how the circuit works - the pot generates a half supply voltage,
and the LEDs just either add a bit or subtract a bit(depending on which
has more light) to that half supply voltage.
Ben
> How can two reverse biased diodes work? --|<|--|>|--
>
> This has bugged me for a while. You had this in your schematic.
> --
>
>
> Ben Hitchcock wrote:
> >
> > I have done something very similar. Check out
> > http://wollongong.apana.org.au/~ben/alf/schematic.html
> >
> > And guess what? Your idea does work, and work very well.
> >
> > Ben
>
> Richard Piotter
> richfile@rconnect.com
>
> The Richfiles Robotics & TI web page:
> http://members.xoom.com/richfiles
>
> (I'm going on an HTML-a-thon today! :)
--
Nothing is foolproof to a sufficiently talented fool.
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