A little context: This is part of a bigger project about glowing algae, my job is to design a photodiode array to measure the amount of light the algae produce in response to movement.
I have a good idea of which photodiode I'm gonna use, the S2387-16R, and my plan is to connect them to the DDC1128 Evaluation Module. This thing is a beast, it can measure ridiculously small currents, in the order of femto-Amperes, so I don't need to use amplifiers.
What I'm trying to find out is what would be the maximum amount of light I could possibly detect. I know that:
$$ I_{max} = \frac{V_{bias}}{R_{Load}} $$
And here is where I need help. How do I connect the photodiode to the Evaluation Module?.
To help explain my question, here is the equivalent circuit of a photodiode, I took it from here.
Everything but \$R_L\$ are internal variables of the photodiode.
Now, at first I thought that \$R_L\$ would be the internal resistance of the Evaluation Board, which I don't know and it's not in the Data Sheet but then I thought: "this is like an Ammeter right?, and those are made to have negligible resistances compared to what you are measuring, right?, so I can just ignore the internal resistance".
If that's the case, then I can put some resistance I know, like 1 kOhm, in one of the terminals of the photodiode, connect that to the Evaluation Module, then connect the other terminal to ground, and that's it.
But I'm not sure that's the case, and if I say to the team that we can ignore the internal resistance of the Evaluation Module and I'm gonna have to justify it and justify it well.
And if I have to consider its internal resistance, what do I do? What would you do?
