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Please explain to me how this light meter work

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Thunderhorse312

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Hi could somebody please explain this circuit. I do not know how to where to measure an output from this circuit by simulating it to multisim, where can i get data. could any body please tell me how. Thanks! Light meter.JPG

This is a brief explanation of the circuit:
This logging circuit is adapted to a battery-powered light
meter in Figure 18. An LM10, combined op amp and reference,
is used for the second amplifier and to provide the
regulated voltage for offsetting the logging circuit and powering
the bias current compensation. Since a meter is the
output indicator, there is no need to optimize frequency
compensation. Low-cost single transistors are used for logging
since the temperature range is limited. The meter is
protected from overloads by clamp diodes D2 and D3.
Silicon photodiodes are more sensitive to infrared than visible
light, so an appropriate filter must be used for photography.
Alternately, gallium-arsenide-phosphide diodes with
suppressed IR response are becoming available.
 
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You can measure the output from the circuit by replacing the meter "M1" with a very low value resistor (0.1 ohm) and then measure the current flow through the resistor.
 

You can measure the output from the circuit by replacing the meter "M1" with a very low value resistor (0.1 ohm) and then measure the current flow through the resistor.

Thanks.. am i correct that whenever there is light the photodiode will convert it to voltage output and would then input to my LM11C.. Could you please clarify if i am correct. Also, how does the LM10 help offset and regulate the input voltage? thanks!
 

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