(MOVED) Photodiode amplifier question

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n289se

Joined Jan 16, 2018
5
amp.png

In the above image, I've drawn out a prototype (?) schematic for a photodiode amplifier. This is a departure from what would normally be used since I am intending on using only discrete transistors as the amplifying devices for this preamplifier stage. I would like to know how to calculate V_out/I_in given the values of R1 through R6. R1 and R3 could be changed as well.

I previously posted this in the "projects" section of this site but I believe it belongs here instead.
 

Alec_t

Joined Sep 17, 2013
11,758
Assuming I_in is the photo-diode current, an LTspice sim gives dv/di as ~ 0.25V per uA with the component values shown :-
IV-plot.PNG
 

Alec_t

Joined Sep 17, 2013
11,758
The relationship would be quite complicated (unless you make simplifying assumptions), since the current gain of the transistors and circuit temperatue would play a role.
 
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