Chapter 4 problems

4.20

• We want to establish a DC operating point for the BJT. Writing a loop equation gives us -V_BB-V_in(t)+i_BR_B+v_BE=0. To form a load line, we will let v_in(t)=0 & i_B=0. Thus v_BE=V_BB+v_in(t) and i_B(t)=(V_BB+v_in(t))/R_B

• $V_{i}n=-0.2,0,0.2$ for the minimum, Q-point and maximum values.