Why the bandwidth is the same of the two circuit?

[ZengLei]

The are two negative feedback circuits
one is the inverting one,the othe is the non-inverting one

But why the bandwidth of the two circuit is the same??

i read this article in this website:

http://www.ecircuitcenter.com/Circuits/op_bandwidth1/op_bandwidth1.htm

why we calculate the bandwidth use the noise gain rather than the voltage gain?

thanks

 

[e_eja]

i thing if we look at an ideal op amp for non inverting and inverting opamp the gain will be diffrent. But if we look at the basic feed back system the equation for both circuit is the same

G=A/(1-AB)

 

[hbaocr]

Hello ,ZengLei
usually , if we the gain of your circuit Is K and the bandwich of that circuit is W , Arcoding to me , I regconize that
K*W ~ const
so if you increase K , it'll cause to decrease W.
but in this case ,there is no the large different levels between two circuits( R2/R1 >>1).So we can consider that they are the same gain so W does not change .that the reason why bandwidth is the same of the two circuit
cheer

 

[zeeshanzia84]

Yes, actually I agree with the reply of the previous post.

Gain-BandWidth product of the OPAMP is constant....if you decrease the gain, the bandwidth increases and vice versa.

Here, in both the circuits if you keep the Gain (its absolute value) same, the bandwidth is also same. So, if both OPAMPS are the same; the bandwidth will also be the same, if you keep the gain equal.