Analyzing current-series negative feedback using voltage gain confusion
Perhaps the shown block diagram can help to clarify the situation? (The last - most right - block should contain a minus sign).
In the diagram I have set Ie=Ic. Of course, we could include the base current into the diagram - however, this would not influence the feedback loop. Note the loop gain is Aloop=-gm*RE.
The circuit establishes current-controlled voltage feedback. (I do not like expressions like &quot;series-parallel&quot; or &quot;parallel-parallel&quot; or....because some authors are counting input-output and some others output-input. So it is somewhat confusing, I think).