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Steve Taranovich

Simple Circuit Measures Relative Intensity of Two Light Sources

Steve Taranovich
12/19/2018 2:34:41 PM
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Re: Clarification please
Hi David,

I have asked the author to comment.

David Ashton
David Ashton
12/19/2018 2:03:18 PM
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Clarification please
Very neat circuit, and I can see applications for comparing temperatures as well.

But the output is given as VIN x 50K x ((1/LDR1)-(1/LDR2))

Yet in the scope traces, VOUT only appears when VIN is zero.

So why wouldn't you ground VIN permanently and just use the polarity of VOUT as your indicator?  Is there any point in changing VIN?

I get the feeling I am missing something here (happens a bit... :-)

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