Question

Electronics 2, a)

The circuit below (Figure 1) shows a phase-shift Oscillator. 1. Delimit the basic oscillator circuit. 2. What are the extra components used for? Why are they needed? 3. Calculate the frequency of oscillation of this circuit? 4. What is the condition that needs to be satisfied to sustain oscillations? 5. What is the optimal number of RC networks needed for a proper operation of such oscillator? Briefly explain your answer. 50 ΚΩ 100 k12 PI V + R D A R2 16 nF 16 nF 16 nF HH HH HI -ovo C R10k R310 k R D2 * R

Answer 1

me tn put Soke + \6nF IGRE 가 Tont Torn Ilona Lh The output voltage amplitude is determined by the amplities manimum output swing, the normal phase shikt oscillator with out diodes) has high distortion amplitice output saturation limits due to The entra diodes used to limit the distortion and reduce the output voltage to acceptable limits ie amplitude stabilization circuit is used this purpose (3 to = (since 8, = 2 of C ==C) ZIRCON where N is 'Rc networks N=2 fo 4TRC 4x3 4xloxloxloxin STIRC exz Thos 457-61142

4 condition such sustained oscillations رن for sustained oscilitions, the told phase shibt around the loop should be 360 Cosso i, The loop gain (ABl = So The amplinier gain = Rf=29 2=298=29xloxlu = 290kn minimum number of Rc networks for Proper ofeeation of these shift oscillatos is three since Three Rc networks Provides Combine Phase shift of 180 & another 180 phase shift provided by amplitice lor ame) total phase shift around the doop is 360 inosder to get sustained oscillations- so