QUESTION BANK FOR ELECTRONIC DEVICES AND CIRCUITS

BRANCH:- 3rd SEM COMPUTER SCIENCE

UNIT- 1

Q. 1 Explain the mobility and conductivity.

Q. 2 Explain Hall Effect and its application.

Q. 3 Explain continuity equation with suitable diagram and mathematical relation.

Q. 4 Explain the significance of Fermi Energy level in intrinsic and extrinsic semiconductor.

Q. 5 If a p-type semi-conductor base has width 5mm and thickness 3 mm. Find the mobility of hole when bar resistivity 200 KΩ –cm, the magnetic field is 0.1 Wb/m2.

Q. 6 In an N-type semiconductor, the Fermi level lies 0.3 eV below the conduction band at 27 °C . If the temperature is increased to 55 °C, find the new position of Fermi level.

Q. 7 How diodes can be used as circuit element, and explain the load line concept.

Q. 8 Explain the negative clipper circuit with suitable circuits.

UNIT-2

Q. 1 Expain the Ebers- Moll model of transistor.

Q. 2 Draw and explain the biasing circuits in case of (I)fixed bias(ii) fixed bias with emitter resistor RE in series with emitter and reference ground, (iii) collerctor to base bias . Derive expression for stability factor S in terms of circuit components for the above circuits.

Q. 3 Explain the thermal resistance and thermal stability of a power transistor circuit. What is the power dissipation condition to prevent thermal runaway.

Q. 4 Derive the expression for Ic versus Ib for common Emitter transistor configuration in the active region .

Q. 5 Define the following regions in a transistor: (a)active, (b)saruration, (c)cut-off

Q. 6 Deduce expressions for Av, Ai, Ri, and Ro in a Common Emitter BJT amplifier in terms of h- parameters.

Q.7 Draw the circuit of transistor in common emitter configuration of BJT and sketch the output characteristics indicates the active, saturation and cutoff region. Derive the relationship between α and β for BJT.

UNIT- 3

Q.1 Draw the R-C coupled amplifier circuit. Calculate the current gain for low, middle and high frequency region.

Q. 2 Explain the working of N-channel MOSFET. What is the difference between enhancement and depletion mode of operation.

Q. 3 Explain Miller’s theorem. Define Boot- strapping with its electrical equivalent circuit?

Q. 4 derive the following for the emitter follower circuit: 1. Avf 2. Rif 3. Rof

Q. 5 Explain the working of FET as a voltage variable resistor(VVR).

Q. 6 Differentiate between FET and BJT.

Q. 7 Draw and explain the small signal model for FET.

UNIT-4

Q.1 Explain the effect of negative feedback on gain and frequency response of an amplifier with help of suitable diagram.

Q.2 Discuss the voltage/current—series/shunt feedback connections with expression for gain, input resistance and output resistance.

Q.3 What is feed back and what are feed back amplifiers?

Q. 4 What are the advantages and disadvantages of negative feed back?

Q. 5 Differentiate between voltage and current feedback in amplifiers?

Q. 6 Give the topology of current amplifier with current shunt feedback?

Q. 7 State and Explain the Nyquist criterion for feedback amplifiers.

Q. 8 Determine the voltage gain, input and output amplifier with feedback for Voltage series feedback having A =-100, Ri=10kΩ, Ro=20 kΩ and β= -0.1

UNIT- 5

Q.1 What are the conditions for sustained oscillator or what is Backhouse criterion?

Q. 2 What are the classifications of Oscillators?

Q. 3 explain the operation of Hartley oscillator.

Q. 4 Find the value of inductor in the Colpitts oscillator if c1=0.2μf, c2=0.02μf And the frequency of the oscillator is 10 kHz. Find the required gain for Oscillator?

Q. 5 Give a short note on crystal oscillator?

Q.6 Explain Schimtt trigger circuit.

Q. 7 With a neat sketch, explain the working of 1. Astable multivibrator 2. Monostable Multivibrator 3. Bistable multivibrator

Q. 8 With a neat circuit diagram explain the working of RC phase shift oscillator.Derive the expression for its frequency of oscillator?