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calculating gain in an op amp

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shinuru

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calculating gain op-amp

how do you calculate gain in an op amp if you know the resistance in kΩ? is there some standard methodology or formula i am missing? my text doesnt tell me how it just assumes i know how to. thanks in advance.
 

Davood Amerion

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we have 2 satandard op-amp amplifier configuration.
one for inverting and one non-inverting.
in inverting amplifier voltage gain is
Av= -Rf/Ri
Rf is feedback resistor from output pin to pin (-).
and Ri is input resistor between input and pin (-).
pin (+) connected to ground.
if we put Rf in kilo ohm in formula then we must put Ri in Kilo ohm too.

and for non-inverting amp
Av= 1+Rf/R2
where Rf placed between output and pin (-)
and R2 placed between pin(-) and ground
pin (+) is input.
 

    shinuru

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Naveed Alam

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mainly two configuations are used..
formulas for both are different...show any schematic, regarding this,...
 

v_c

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Please take a look at the document called "Opamps for Everyone" edited by Ron Mancini of Texas Instruments. Here's a link to this document

https://www.web-ee.com/primers/files/slod006b.pdf

I suggest that you take a look at Chapter 3 (and Chapter 2) if you need to review some basic concepts.

I hope that you find this material helpful.

Best regards,
v_c
 

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