Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: speaking of LEDs
Message-ID: <1988Oct4.161725.15471@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1988Oct2.053515.18004@utzoo.uucp> <1652@eos.UUCP>
Date: Tue, 4 Oct 88 16:17:25 GMT

In article <1652@eos.UUCP> jbm@eos.UUCP (Jeffrey Mulligan) writes:
> [red vs green LEDs, efficiency etc.]
>For the caving application, you would probably want to compute the
>luminous efficiency using the scotopic luminosity function (rods
>instead of cones).  This would shift the balance towards green
>by 1-2 orders of magnitude.

I'd be somewhat surprised if it were that large, based on some tinkering
with LEDs in low light levels... but I agree that this is the right way
to answer the question.  Better than computing the efficiency, actually,
would be to experiment, which would also give you some idea of what the
lowest usable light levels would be.
-- 
The meek can have the Earth;    |    Henry Spencer at U of Toronto Zoology
the rest of us have other plans.|uunet!attcan!utzoo!henry henry@zoo.toronto.edu