1) Consider an inverting operational amplifier as shown in figure. Suppose R1= 1000 ohm & R2 = 10^6 ohm. It is said that the input impedance=R1=1000 ohm and the Output impedance= 0. But for an Op-Amp, the input impedance is infinite isnt it?
2) Consider a non inverting operational amplifier as shown in figure. Suppose R1= 3500 ohm & R2 = 15000 ohm. It is said that the input impedance=infinite. Why is it so? Here R2 is the feedback resistor.
As I am unable to upload the image, I am providing a link to site that contains the diagram of both inverting & non inverting operational amplifier.
http://webpages.ursinus.edu/lriley/ref/circuits/node5.html
2) Consider a non inverting operational amplifier as shown in figure. Suppose R1= 3500 ohm & R2 = 15000 ohm. It is said that the input impedance=infinite. Why is it so? Here R2 is the feedback resistor.
As I am unable to upload the image, I am providing a link to site that contains the diagram of both inverting & non inverting operational amplifier.
http://webpages.ursinus.edu/lriley/ref/circuits/node5.html