Lösning:

U_{in} = r_{\pi} I_{b} + R_{E1} \left(I_{b} + \beta_{ac} I_{b}\right) \quad \text{och} \quad U_{ut} = - \beta_{ac} I_{b} \left(R_{C} // R_{L}\right) g_{m} = \frac{I_{CQ}}{V_{T}} = \frac{1,05\ \mathrm{m}}{25\ \mathrm{m}} = 42\ \mathrm{m}\Omega^{-1} A_{v} = \frac{U_{ut}}{U_{in}} = - \frac{\beta_{ac} \left(R_{C} // R_{L}\right)}{r_{\pi} + R_{E1} \left(1 + \beta_{ac}\right)} = - \frac{g_{m} \left(R_{C} // R_{L}\right)}{1 + R_{E1} \frac{\left(1 + \beta_{ac}\right)}{r_{\pi}}} \approx - \frac{g_{m} \left(R_{C} // R_{L}\right)}{1 + g_{m} R_{E1}} A_{v} \approx - \frac{g_{m} \left(R_{C} // R_{L}\right)}{1 + g_{m} R_{E1}} = - \frac{42\ \mathrm{m} \cdot 4,27\ \mathrm{k}}{1 + 42\ \mathrm{m} \cdot 470} = -8,65\ \mathrm{g\ g\ r}

Inresistansen: $R_{in} = \frac{U_{in}}{I_{in}} = R_{1} // R_{2} // \frac{U_{in}}{I_{b}} = R_{1} // R_{2} // (r_{\pi} + R_{E1} \left(1 + \beta_{ac}\right)) = 7,5\ \mathrm{k}\Omega$

Utresistansen: $R_{ut} = R_{C} // R_{L} = 4,27\ \mathrm{k}\Omega$