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Photodiode/Multisim Help needed.

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USMCinfinity

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Can someone tell me whats wrong with this circuit? ...Please don't be harsh, I'm very tired. Every time I click play the capacitor goes bye bye.

 

alexan_e

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Are you sure that the R4 resistor should be connected between the positive input and negative power supply (instead of ground)

Alex
 

FvM

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Are you sure that the R4 resistor should be connected between the positive input and negative power supply (instead of ground)
Also besides this point, I'm unable to detect a reasonable circuit operation, You should explain first what you are trying to achieve. If the 45 uA current source is intended as photo current simulation, at has the wrong polarity.
 

USMCinfinity

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I'm trying to simulate this circuit.

Here it is with what you guys told me, the current isn't really doing anything...

 

alexan_e

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Here it is with what you guys told me, the current isn't really doing anything...
Read again this comment

If the 45 uA current source is intended as photo current simulation, at has the wrong polarity.
I have seen a circuit using a photodiode but it was actually reversed as FvM said

photometer2simple.jpg

Alex
 

USMCinfinity

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I did change the polarity in the other one I put. Changing the diode's polarity too gives the result below.

 

alexan_e

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What is the output you expect from the circuit?
Why is the multimeter connected between the negative input of the opamp and the output?

Alex
 

FvM

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You have now presented three different photodiode/OP connection variants. One of them (the second) is correct in so far, that the current source places the photodiode in forward bias. But the overall circuit is still wrong, as Alex mentioned in his first post. Unfortunately we don't knów, what you exactly want to achieve.
 

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