(Solved):
Consider the two stage differential amplifier with feedback in the figure below. The first stage i ...
Consider the two stage differential amplifier with feedback in the figure below. The first stage is a differential amplifier and the second is stage is a difference amplifier. Assume \( \beta=60, R_{B}=19.3 \mathrm{k} \Omega, R_{C}=10 \mathrm{k} \Omega, R_{3}=300 \mathrm{k} \Omega, R_{4}=100 \mathrm{k} \Omega, R_{1}=0.1 \mathrm{k} \Omega_{r} \) and \( R_{2}=1 \mathrm{k} \Omega \). You may ignore the early voltage effect. What would be the estimate input impedance of the feedback amplifier? a. close to \( 350 \mathrm{k} \Omega \) b. close to \( 42 \mathrm{k} \Omega \) c. close to \( 100 \mathrm{k} \Omega \) d. close to \( 20 \mathrm{k} \Omega \) e. close to \( 10 \mathrm{k} \Omega \)