3. Calculate the junction capacitance of a pn junction.
(2 Points)
Consider a silicon pn junction at $T=300 \mathrm{~K}$, with doping concentrations of $N_{a}=2 \times 10^{16} \mathrm{~cm}^{-3}$ and $N_{d}=5 \times 10^{15} \mathrm{~cm}^{-3}$. Assume that $n_{i}=1.5 \times 10^{10} \mathrm{~cm}^{-3}$ and let $C_{j 0}=0.6 \mathrm{pF}$. Calculate the junction capacitance at $V_{R}=2 \mathrm{~V}$.
4. Determine the diode voltage and current in the circuit shown in Figure 1, using a piecewise linear model. Also determine the power dissipated in the diode. (10 Points) $V_{s}=5 \mathrm{~V}, R=2 \Omega$ Assume piecewise linear diode parameters of $V_{\gamma}=0.6 \mathrm{~V}$ and $r_{f}=10 \Omega$.
Figure 1: Question 4.
