For the circuit of Fig. 9.41, parameter values are R_F= 5 kΩ, R_E= 50 Ω, and C_F= 1.5 pF. The basic amplifier of the circuit is shown in Fig. 9.42 and has two negative real poles with magnitudes 3 MHz and 6 MHz. The low-frequency current gain of the basic amplifier is 4000. Assuming that the loop gain of the circuit of Fig. 9.41 can be varied without changing the parameters of the basic amplifier, sketch root loci for this circuit as f varies from 0 to 0.01 both with and without C_F. Estimate the pole positions of the current-gain transfer function of the feedback amplifier of Fig. 9.41 with the values of R_Fand R_Especified both with and without C_F. Sketch graphs in each case of gain magnitude versus frequency on log scales from f = 10 kHz to f = 100 MHz.

Figure 9.41:

Figure 9.42:

Q2 RE Rp Cf w- Q2 Q1 R11 RE CF RF is CF Rf E RE