(Solved): a. The superposition theorem is applicable for the analysis and design of the dc and ac components ...

a. The superposition theorem is applicable for the analysis and design of the dc and ac components of a BJT network, permitting the separation of the analysis of the dc and ac responses of the system. However, the ac analysis of BJT networks will be determined by the dc conditions. The key to transistor small-signal analysis is the use of the equivalent circuits (models). A common emitter configuration B.JT amplifier uses a NPN transistor shown in Figure Q4(a). Figure Q4(a) A Common Emitter BJT amplifier Given the parameters for this common emitter configuration above, \( R_{1}=56 \mathrm{KO}, R_{2}=8.2 \) \( \mathrm{K} \Omega, \mathrm{Rc}_{\mathrm{c}}=4.3 \mathrm{K \Omega}, \mathrm{Re}^{2}=1.5 \mathrm{K \Omega}, \mathrm{Rs}=1 \mathrm{kn}, \mathrm{Vcc}=24 \mathrm{~V} \), Capacitor \( \mathrm{C}_{1}=\mathrm{C}_{2}=10 \mu \mathrm{F}_{2} \mathrm{C}_{3}=15 \mathrm{uF} \), \( r o=60 \mathrm{~K} \Omega, \beta=100 \) (i) Draw the equivalent DC circuit and determine \( r_{e} \) value. (ii) Draw the equivalent \( \mathrm{AC} \) circuit using \( r_{e} \) transistor model. (6 Marks) (4 Marks) (iii) Determine input impedance \( Z_{i} \) and output impedance \( Z_{o} \).