I was learning about noise analysis of opamp with the help of this document.It says that for Noise Gain In op-amp circuits, noise is commonly assigned to the non-inverting op-amp input. But no explanation why.
Can you please tell me why it is always referred to non inverting input
It can be assigned to either input (or both if you want to be masochistic) but, the non-inverting input is chosen because it more readily suits the majority of circuit applications and, is therefore easier to analyse. It's purely a matter of convenience and, you would get the same result if you assign it to the less convenient inverting input.
