4. (15%) While \( V{C} \) denotes the DC component of the output voltage, \( v{0} \) and \( v{1} \) denote the AC components of the output and input voltages. Determine the small-signal voltage gain \( A{\nu} = v{0} / v{1} \) of the BJT amplifier shown in Fig. 4. Assume the thermal voltage \( V{\mathrm{T}} = 25\mathrm{mV} \), \( V{\mathrm{BE}} = 0.7\mathrm{V} \), \( \beta = 100 \).