Consider the noninverting op-amp circuit in Figure P12.18. The input resistance of the op-amp is Ri = ∞ and the output resistance is Ro = 0, but the opamp has a finite gain A.
(a) Write the closed-loop transfer function in the form
![](https://test.transtutors.com/qimg/2ebfee59-edc6-48bc-b8c1-c63c29aeb93e.png)
(b) What is the expression for β?
(c) If A = 105 and Av f = 20, what is the required β and R2/R1?
(d) If A decreases by 10 percent, what is the percent change in Av f ?
![2268_Figure 5.jpg](https://secure.tutorsglobe.com/CMSImages/2268_Figure 5.jpg)