Re: Linear light-sensing circuit required

"Steve J. Noll" <sjnoll@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:gu7091pb15r9v3u4bqfq56fuijc58p2rbp@xxxxxxxxxx
> On Sun, 22 May 2005 00:05:56 GMT, "Kryten"
> <kryten_droid_obfusticator@xxxxxxxxxxxx> wrote:
>
> Use in current mode to be linear.

Yes, I felt this was the better way to go

> Just need a transimpedance amp.
> Basically, one op amp and one feedback resistor.

I was thinking of tying cathode to + input, anode to - input,
resistor between output and - input.
Also tie + input to idle voltage (as a virtual earth).

Like so: http://www.elecdesign.com/Files/29/4479/Figure_01.gif
from article http://www.elecdesign.com/Articles/ArticleID/4479/4479.html

AFAICS, this ought to do it: the op-amp should pull the output voltage lower
as the PD tried to force current into the - input node.

I guess this is what you meant too, and not one of those unusual
transconductance op-amp thingies.

K.


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