Question

4. Given the tuned circuit and two amplifier configurations below: a) Which amplifier configuration will oscillate with tuned circuit and why? b) What is the frequency of oscillation and the feedback factor (B)? ナVOD RFc 300200 CITT CHT #2

Answer 1

(a) in the given two circuits circuit 1 will oscillate and turned particular frequency because it has leed back path between input and output when we connect turned circuit between point A and point b But in circuit 2 point A and B has between source and drain terminals of the transistor so we connect turned circuit we not have a closed loop (or) feedback network so circuit 1 only produce oscillation or circuit is only work has oscillator so circuit became \r\n the circuit 1 simply act as a culprits oscillation (b) frequency of oscillation I_r = 1/squareroot L . (c_1 C_2/C_1 + C_2) C_T = C_1 C_2/C_1 + C_2 = 300 times 10^-12 times 200 times 10^-12/300 times 10^-12 + 200 times 10^-12 = 1.2 times 10^-10 therefore I_n = 1/squareroot 200 times 10^-6 times 1.2 times 10^-10 = 1/2 pi squareroot 2.4 times 10^-14 = 1/9.73 times 10^-7 I_n = 1.02 mHz