Analog questions

1. What is Barkhausen criterion for oscillator to produce oscillation?
2. Explain phase shift oscillator: (a) using FET (b) using BJT (c) using op-amp? What are advantages and disadvantages of phase shift oscillator?
3. Explain resonant ckt. Oscillator?
Or Explain L-C oscillator?
Or explain (a) tuned collector i.e. using BJT and tuned drain i.e. using a FET oscillator?
4. A tuned collector oscillator has a fixed inductance of 100Hμ and has to be tunable over the frequency band of 500 KHz to 1500 KHz. Find the range of variable capacitor to be used?
5. What is the use of grid leak biasing in resonant ckt. Oscillator?
6. Explain colpitts oscillator?
7. Explain Hartley oscillator?
8. Why colpitts oscillator is more stable than Hartley oscillator?
9. Explain crystal oscillator. What are the advantages and use of crystal oscillator?
10. Explain frequency stability of an oscillator?
11. What are the differences between voltage and power amplifier?
12. Explain class A power amplifier?
13. Explain second order harmonics in class A amplifier?
14. An output waveform of a power amplifier displayed on oscilloscope has following measurements values: IC-min.=1.2A, IC- max.=22A and ICQ= 10A.
Find second order harmonics.
15. In a class A power amplifier total output current for input signal of x= 1.95 sin 400t, is gives by:
IY= (35+12 sin 400t+ 1.2 sin 800t+ 0.9sin 1200t+ 0.4sin1600t) Amp.
Find (i) total harmonic distortion. (ii) Percentage increase in output due to distortion(harmonics).
16. In a class A amplifier total output current is given as
iY = (35+ 17 cos wt+ 10 cos 2wt+ 0.3 cos 3wt) mA
if RL= 2.2 K ohm then find (a) total distortion, D
(b) Power delivered to load at fundamental frequency.
(c) Total power delivered to load
17. Explain transformer coupled class A Amplifier? Its advantages over series fed class A amplifier.
18. Explain impedance matching in transformer coupled class A Amplifier?
19. Why generally a step down transformer is used in transformer coupled class A Amplifier.
20. A transformer coupled class A Amplifier has maximum and minimum value of collector- emitter voltage of 25 V and 2.5 V. Determine collector efficiency?