ELECTRONICS AND COMMUNICATION ENGINEERING Questions Bank 2014

Anna University, Chennai

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PART B

1, Explain Bistable Multivibrator and its types?

General form of bistable Multivibrator circuit.

· fixed Bias transistor bistable Multivibrator circuit

· self Bias transistor biastable Multivibrator circuit

· Applications

2, Explain about speedup capacitors or commutating capacitors

· Practical self biased bistable Multivibrator

· Explanation about the circuit

3, Explain about Monostable Multivibrator

· Explanation about the circuit diagram

· Pulse width of collector coupled Monostable Multivibrator

· Wareforms

· Applications

4, Explain about collector coupled astable Multivibrator

· Explanation about the circuit diagram

· Wareforms

· Distration & its eliminator

· Applications

5, Explain emitter coupled astable Multivibrator

· Operation and Mathematical analysis

· Practical circuit

· Advantages and disadvantages of the Multivibrator

6, Write in detail about Schmitt Trigger circuit?

· Circuit diagram

· Operation of the circuit

· Schmitt trigger wareforms.

· Hysterisis

· Applications

7, Explain about pulse transformer?

· Ideal pulse transformer model

· Practical equivalent circuit

· Pulse response characteristics

· Applications of pulse transformer

8, Explain Monostable blocking oscillator using emitter timing?

· Circuit Diagram

· Mathematical analysis

· Expression for pulse width

· Triggering circuit for monostable blocking oscillator

9, Write about the core saturation method

· Circuit diagram

· Waveforms of ic and iB when core Saturates.

10, Write about astable blocking oscillator.

· Diode controlled astable blocking Oscillator

· RC controlled astable blocking Oscillator

11, Write about UJT sawtooth generator

· Operation

· Circuit diagram

12, What will happen when a step input voltage is applied to the high pass RC Circuit?

· Derivation

· The output Waveform

13 .Explain the relevant information ,how the negative feed back improves stability reduce noise and increase input impedance?

Draw the circuit diagram. Explain detail the following

· transfer gain.

· stability of gain.

The transfer of gain of the amplifier is not constant as it is depends upon the factors such as operating point temperature ,etc. This lack of stability can be reduced by introducing negative feed back.

The signal feed back reduces the amount of the noise signal and non linear distortion. The factor (1+bA)reduces both input noise and resulting non linear distortion for considerable improvement. Thus ,noise and non linear distortion also reduced by same factor.

14.Explain voltage shunt feed back amplifiers?

¾ Draw the circuit diagram.

¾ Draw the equivalent circuit .

¾ Find the input and output impedance after feed back.

15.Explain current series feed back amplifiers?

· Draw the circuit diagram.

· Draw the equivalent circuit .

· Find the input and output impedance after feed back.

16.Explain the classification of amplifiers?

Explain the following in detail. ¾ Voltage amplifier.

¾ Current amplifier.

¾ Trans conductance amplifier.

¾ Trans resistance amplifier.

17.Explain current shunt and voltage shunt feed back amplifiers?

¾ Draw the circuit diagram.

¾ Draw the equivalent circuit .

¾ Find the input and output impedance after feed back.

18. With simple diagrams explain the operation of negative resistance oscillator using tunnel diode?.

¾ Draw the circuit diagram and graph.

¾ Draw the characteristics of tunnel diode.

¾ Get the expression for time period ‘t’.

¾ Draw the wave form for negative resistance oscillator.

19. Explain RC phase shift oscillator?.

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the minimum value of hfe for oscillation.

20. Explain Clapp’s oscillator and derive the expression for frequency of oscillation . Also explain how frequency stability can be improved Clapp’s oscillator.?

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the frequency of oscillation.

21. Explain Hartly oscillator and derive the equation for oscillation ?

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the frequency of oscillation.

22. Explain pierce crystal oscillator and derive the equation for oscillation?

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the frequency of oscillation.

23.Explain in detail about single tuned amplifier?

· Draw the circuit diagram

· Draw the equivalent circuit.

· Derive the expression for band width

24. Explain in detail about double tuned amplifier

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the expression for band width

25. Explain in detail about stagger-tuned amplifier

¾ Draw the circuit diagram

¾ Draw the equivalent circuit.

¾ Derive the expression for band width

26. Compare single tuned and double tuned amplifier

¾ Compare the circuit diagram

¾ Compare the equivalent circuit.

¾ Compare the expression for band width

27. Explain the different types of neutralization?

¾ Explain Hazeltine neutralization

¾ Explain Rice neutralization.

¾ Explain Neutrodyne neutralization