1.in some circuits there used to be one resistor between photo diode and inverting terminal of op amp. what is the advantages..
Assuming the opamp is configured as a current to voltage converter, the resistor's only function is likely to be as a protection device. It can limit the fault or transient current through the opamp input protection diode.
Hi, suresh bel.
There are two reasons why a resistor is connected between the photodiode and amplifier.
1. The resistor acts as a bias resistor wherein it compensates for the bias current of the amplifier.
2. The resistor, which is usually very high (100Mohms), acts as the shunt resistance of the photodiode junction.
Hope this helps. Let me kow if you have other concnerns.
Apology for this very late reply.
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