V}{{{V_T}}}}}\)By APPLYING KCL at NODE O,\(I = \frac{{0 - {V_{out}}}}{{1k}} = {I_o}{e^{\frac{{{V_{in}}}}{{{V_T}}}}}\)\(\Rightarrow {V_{out}} \propto {e^{\frac{{{V_{in}}}}{{{V_T}}}}}\)