Question

Examine the frequency characteristic of an audio frequency oscillator by varying the component's values, as shown in Fig. 3.1. (1+1) The following data is available. B=1/3, R1=40-49k12, R2=45-52k 2, C1=0.001-0.003 uF, C2=0.002-0.005uF. Figure out the resonance frequency as well based on data variability. (1+1) Explain why this kind of oscillator only operates at resonance frequency. Aid with circuit explanation. (2) Rf Ri vo + 디 RI & R2 Fig. 3.1

Answer 1

Rf MW At R, R = 45.52ha, gioen ß= 7, R = 40-49kr G=0.001-0.003 ef = 0.002-0.005 MF Answer is given circit is a weinbridge oscinates " Inorder to get sustained oscillations it should follow Barkhausen criterion i, gan should be eaed to A=3 ieß="₂ doorgain AB Total Phase shikt around the loop is either S os 360 It Rf = 3 > R=2 Re=2R; Ri TR;= loke) / Re=roka The resonance frequerly for & JR GRE RF 40, R=45kn, oooluf, = 0.0024F fo= 2.65 kHz max

toa 2-т со все = = 41, S2 ч. с = o so34 € = o-oo Sяг $ = 1 + о не min