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Biasing of Op-amp if Audio Amplifier

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umesh49

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Hi,
I am not a expert in Amplifeir based circuit, and confused with seing a audio amplifier circuit. I had seen that input is connected through op-amp non-inverting via a capacitor. From where op-amp is getting its biased current supplied in this circuit as capacitor will block any DC?
 

KerimF

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Do you mean just a capacitor is connected to the IN+ of an opamp?... If so I wonder if the amplifier can work linearly and be stable, unless that capacitor is lossy so it also provides a DC path.
 

umesh49

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Yes, I meant that capacitor, and I read some where that we sohuld provide some return path for biased current, but from where biased current is supplied.
I have seen audio amplifier circuit and I did not found if it would be written that biased current will be through capacitors leakage.
 

KerimF

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You are right to be confused...
In this case only a real experiment that you can build can give you the right answer.
You know, there are many reasons that let a schematic be not complete as intended therefore it cannot reflect a real working circuit.
For instance, serious discussions can be shared if a schematic is fully clear for all sides.
 

FvM

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Two comments:
- are you sure, you are talking about a standard OP amp? There are many special devices for audio applications that have internal bias. You can refer to LM386 as a popular example. I don't think, that the problem can be discussed seriously without knowing the part number
- in any case, I would prefer to see a schematic
 

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