In the circuit shown below, the input voltage V${_i}{_n}$ is positive. The current (I) – voltage(V) characteristics of the diode can be assumed to be I = I${_0}$e$^{v/vr}$ under the forward bias condition, where V${_T}$ is the thermal voltage and I${_0}$ is the reverse saturation current. Assuming an ideal op-amp, the output voltage v${_o}{_u}{_t}$ of the circuit is proportional to
- log${_e}$(V${_i}{_n}/V{_T}$)
- 2V${_i}{_n}$
- e$^{V}{_i}{_n}/^{V}{T}$
- V$^{2}{_i}{_n}$