From: Colin McKie (colinmckie@xtra.co.nz)
Date: 12/31/69-05:59:59 PM Z
"Jeffrey D. Mathias" wrote:
>
>It is better to build an amplifier to amplify the current from the
>device or use a sensitive accurate current meter. The impedance
>matching is key. Measuring the voltage will not give a linear response
>to light flux.
>
Jeffrey,
The main advantage of measuring the Si cell voltage via a high impedance buffer is that it gives a logarithmic response, hence linear in stops (or log density). I use this in a simple transmission densitometer.
I agree CdS is not the way to go, as it is mainly blue sensitive.
Seems to be a lot of IR discussion lately; maybe we need to recruit even more alt-process people to the IR list!
Colin
Mainland Monochrome
http://www.geocities.com/main_mono
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