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