# Why are the considered signal and current input of common base and emitter different although both take $V_{EB}$ as input?

This figure is common-base configuration of pnp (I want to have a pic of npn but can't find one)

The input signal and current are $V_{EE}+v_{eb}(t)$ and $I_E+i_e$

And this is common emitter configuration of npn

The input signal and current are $V_{BB}+v_{eb}(t)$ and $I_B+i_b$

Though different notation, $V_{EE}+v_{eb}(t)$ = $V_{BB}+v_{eb}(t)$

So as the input signal in both configuration are the same, how are the considered currents different. Because the common-base pic is pnp so the direction can look different between 2 picture.

In my textbook, it says in the common base, the small change in input signal (caused by $v_{eb}(t)$ lead to big change in $I_E$. If that's a case then isn't it is the same in common emitter so why the input current in common emitter is $I_B$ but not $I_E$ and different input resistance $r_e$too