- #1

goodphy

- 216

- 8

Hello.

I've studied the golden rules of the feedback OP-AMP and applying this to voltage follower shows that voltage gain (V

Thus, V

I've studied the golden rules of the feedback OP-AMP and applying this to voltage follower shows that voltage gain (V

_{out}/V_{in}) is 1.Thus, V

_{out}should eventually follows V_{in}when V_{in}suddenly changed. I've tried to follow this process for clear feeling by drawing pictures as shown in the attached image.*(or becomes saturation value.) This divergence is even more clear when feedback equation is approximates to (V***Since A**_{V}is very large for typical OP-AMP, It looks V_{out}becomes divergent!_{+}- V_{-})A_{V}^{n}where n is number of looping. (You can get this approximation by looking last shown V_{out}in the image.)**What was I wrong? Why does feedback make the system crazy?**