Andhra University 2010 B.E Electronics

(ii) discuss Hazeltine Neutralization Method. (Marks 6)

14. (a) (i) Sketch and describe transistor switching times. (Marks 8)
(ii) What is a clipper? discuss the operation of positive and negative
diode clippers with waveforms. (Marks 8)
Or
(b) (i) discuss astable multivibrator with neat sketch of waveforms at
collector and base of transistors used in the circuit. (Marks 10)
(ii) Determine the value of capacitors to be used in an astable
multivibrator to give a train of pulse 2µ s wide at a repetition
rate of 100 KHz if R1 = R2 = 20 k one two . (Marks 6)

15. (a) (i) discuss about astable blocking oscillator with base timing. (10)
(ii) The diode controlled astable blocking oscillator has the parameters
=10 CC V V, V V B = 0.5 , n = two , R =1.5K , =10 f R , V V r = nine ,
L = 3mH and C =100 pF . compute the frequency of oscillation and
duty cycle. (Marks 6)
Or
(b) Write about Miller Integrator and Current-Time Base Circuit with
waveform. ((b) (i) discuss voltage series and voltage shunt feedback connections. (Marks 8)
(ii) discuss Nyquist criterion to analyse the stability of feedback
amplifiers. (Marks 8)
12. (a) (i) discuss Armstrong oscillator and derive its frequency of oscillation.
(8)
(ii) A Colpitts oscillator is designed with C 100 pF one = and
C 7500 pF two = . The inductance is variable. Determine the range of
inductance values, if the frequency of oscillation is to vary ranging from
950 KHz and 2050 KHz. (Marks 8)
Or
(b) (i) discuss Wien bridge oscillator and derive its frequency of
oscillation. (Marks 10)
(ii) Write a note on frequency stability of oscillators. (Marks 6)
13. (a) (i) explain about double tuned voltage amplifier. (Marks 8)
(ii) explain the effect of bandwidth on cascading single tuned
amplifiers. (Marks 8)
Or
(b) (i) discuss class 'C' tuned amplifier and derive its efficiency. (Marks 10)
(ii) discuss Hazeltine Neutralization Method. (Marks 6)
14. (a) (i) Sketch and describe transistor switching times. (Marks 8)
(ii) What is a clipper? discuss the operation of positive and negative
diode clippers with waveforms. (Marks 8)
Or
(b) (i) discuss astable multivibrator with neat sketch of waveforms at
collector and base of transistors used in the circuit. (Marks 10)
(ii) Determine the value of capacitors to be used in an astable
multivibrator to give a train of pulse 2µ s wide at a repetition
rate of 100 KHz if R1 = R2 = 20 k one two . (Marks 6)
15. (a) (i) discuss about astable blocking oscillator with base timing. (Marks 10)
(ii) The diode controlled astable blocking oscillator has the parameters
=10 CC V V, V V B = 0.5 , n = two , R =1.5K , =10 f R , V V r = nine ,
L = 3mH and C =100 pF . compute the frequency of oscillation and
duty cycle. (6)
Or
(b) Write about Miller Integrator and Current-Time Base Circuit with
waveform. (Marks 16)

Earning:   Approval pending.