Sketch the graph of small-signal, common emitter current gain versus frequency on log scales from 0.1 MHz to 1000 MHz for the examples of Problems 1.8 and 1.9. Calculate the f_T of the device in each case.

Data from Prob. 1.9:

Repeat Problem 1.8 for I_C = 1 mA, V_CB = 1V, and V_CS = 2 V.

Data from Prob. 1.8:

Derive and sketch the complete small-signal equivalent circuit for a bipolar transistor at I_C = 0.2 mA, V_CB = 3V, V_CS = 4 V. Device parameters are C_je0 = 20 f_F, C_μ0 = 10 f_F, C_cs0 = 20 f_F, β₀ = 100,τ_F = 15 ps, η =10⁻³, r_b = 200, r_c = 100, r_ex = 4, and r_μ = 5 β₀ r_o. Assume ψ₀ = 0.55 V for all junctions.