关键公式
\[I_D = I_{DSS}\left(1 - \frac{V_{GS}}{V_P}\right)^2 \;\text{(JFET饱和区)} \qquad I_D = k_n(V_{GS} - V_{TH})^2 \;\text{(MOSFET饱和区)}\]
\[g_m = \frac{2I_{DSS}}{|V_P|}\left(1 - \frac{V_{GS}}{V_P}\right) \;\text{(JFET饱和区)} \qquad g_m = 2k_n(V_{GS} - V_{TH}) \;\text{(MOSFET饱和区)}\]