$*$Ex $7\mathrm{.}14$: Consider the common$-$base circuit in Figure $7\mathrm{.}64.$ The transistor parameters are $=100,V_{BE}(on)=0\mathrm{.}7V,V_A=,C_{}=24pF,$ and $C_{}=3pF.($a$)$ Determine the upper $3$ dB frequencies corresponding to the input and output portions of the equivalent circuit. $($b$)$ Calculate the small$-$signal midband voltage gain. $($Ans$.($a$)f_H=223MHz,f_H=58\mathrm{.}3MHz,($b$)A_v=0\mathrm{.}869)$

$1(R\frac{B}{r_{}})$

$($ bast$)$

$R\frac{L}{R_c}$