We can use the concept of linear circuits to simplify circuit analysis (e.g. superposition & Thevinin’s theorem.) In order to do this, we need a simple way to identify linear circuits.
I believe this is typically done by recognizing that a circuit is composed entirely of linear components. It makes intuitive sense that linear components would create linear circuits, but is there a more rigorous explanation as to why?
Even if all components are linear (obey additivity and homogeneity,) it’s not clear to me why every input/output relationship in that circuit has to share this property.
