Alt-BEAM Archive
Message #01314
To: davidperry@mail.geocities.com
From: Steven Bolt sbolt@xs4all.nl
Date: Fri, 5 Mar 1999 09:56:08 +0100 (CET)
Subject: [alt-beam] Re: photodiodes
On Wed, 4 Mar 1992 davidperry@mail.geocities.com wrote:
> maybe you should think of them as one way soalr cells, they generate
> around 0.4 volts one way, and the other way it totally blocks the
> electricity, thats the whole point of a diode. I don't know about
> their resistance.
It's not as simple as that...
> > okay, quick question. as far as i know, photodiodes have resistance
> > in only one direction. is the other direction blocking electricity or
> > does it have no resistance?
And there is probably no quick answer to this quick question. But
how about this:
Aach photon within the wavelength range of your photodiode creates an
electron-hole pair. When reverse biased, this results in a current
flow which is proportional to light flux. Meaning that "the other
way," it does not totally block electricity, because it is a
photodiode, not a diode. And you should not associate any of its
properties with simple resistance; that is quite misleading.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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