The feedback current amplifier in Fig.(a) can be thought of as a "super" CG transistor. Note that rather than connecting the gate of Q2 to signal ground, an amplifier is placed between source and gate.
(a) If μ is very large, what is the signal voltage at the input terminal? What is the input resistance? What is the current gain Io/Is?
(b) For finite μ but assuming that the input resistance of the amplifier μ is very large, find the A circuit and derive expressions for A, Ri , and Ro.
(c) What is the value of β?
(d) Find Aβ and Af . If μ is large, what is the value of Af ?
(e) Find Rin and Rout assuming the loop gain is large.
(f) The "super" CG transistor can be utilized in the cascade configuration shown in Fig.(b), where VG is a dc bias voltage. Replacing Q1 by its small-signal model, use the analogy of the resulting circuit to that in Fig(a) to find Io and Rout.
