Alt-BEAM Archive
Message #01507
To: beam@corp.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Sat, 13 Mar 1999 09:44:45 +0100 (CET)
Subject: [alt-beam] Re: FLED solarengine
On Fri, 12 Mar 1999, Hendrickson wrote:
> First of all, a PD (photodiode) conducts better in higher light conditions
> when foward biased (ie. - to -, + to +) and creates a small amount of
> electricity when reverse biased (- to+, + to -) so if you attach enough Pds
> in parallel and reverse biased you can use them to replace solar cells.
That works only with photodiodes which have a large active area,
like the BPW34 and BPW41 (active area's of 7.5mm2).
And note that as sensors, photodiodes are often used in what's
known as `photocurrent mode'; the other parts of the circuit
provide a reverse bias and react to the light-dependent current
passing through the diode when its anode is the negative side.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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