calculating gain in an op amp

[shinuru]

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]

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.

 

[Naveed Alam]

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

 

[v_c]

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

**broken link removed**

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