What is the relationship between the open-loop gain of an op-amp and the closed-loop gain of an inverting amplifier?

 

Hello,

Have a look in the following PDF:
sloa011Understanding Operational Amplifier Specifications.pdf

Bertus

 

Hello,

Have a look in the following PDF:
sloa011Understanding Operational Amplifier Specifications.pdf

Bertus

hey, thanks
can you tell me the specific page it will be gr8...

 

I think this formula can be used for the relationship between CL and OL
Acl=Aol/ (1+B *Aol)

 

What is the relationship between the open-loop gain of an op-amp and the closed-loop gain of an inverting amplifier?

The closed loop gain is controlled by the external components and the open loop gain does not enter into the calculation.

 

The closed loop gain is controlled by the external components and the open loop gain does not enter into the calculation.

Open loop doesnt enter into what calculation?
Can you verify if the formula I posted above is correct?
Thanks

 

The closed loop gain is controlled by the external components and the open loop gain does not enter into the calculation.

Suppose Aol=100k, and the feedback ratio is .001. You actual gain would be ≈1% lower than the value calculated from the feedback resistor ratio. Open loop gain can usually be ignored, but you need to be aware that it is finite.

 

That is true, but we seldom have a closed loop gain that is closer to the open loop gain than say four orders of magnitude. This is like saying I write all my answers to 9 significant figures because I like to be precise.

One of the great benefits of reducing the gain by closing the loop is the corresponding increase in bandwidth.

 

That is true, but we seldom have a closed loop gain that is closer to the open loop gain than say four orders of magnitude.

"Seldom" is the key word here. This is precisely why I said

Open loop gain can usually be ignored, but you need to be aware that it is finite.