Electronic Circuits and Devices Question Paper of 3rd Semester ECE16 Download Previous Years Question Paper 4

Roll No.

Total No. of Questions : 091

B.Tech. (Sem. – 3rd)

ELECTRONICS DEVICES & CIRCUITS

SUBJECT CODE : EC - 201

Paper ID : [2126]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section - A

Ql)

a)     Draw the Ideal characteristics of the Diode.

b)    With the characteristic curves & write briefly about working of photo diode.

c)     Write the advantages of MOSFET.

d)    In a fixed bias circuit

R_B =150kΩ, R_C. = 2kΩ, V_CC = l2V,Transistor is silicon with B=100

then find ‘i_B’.

e)     Write the advantages of class 'AB' amplifier.

f)      In what type of applications tuned coupling are used. ..

g)     What is meant by feed back? What type of feed back is used in oscillator.

h)    write the characteristics of current shunt feedback amplifier.

i)       Draw and explain the general tank circuit of LC oscillator.

j)       Expl4rn Thermal Runway.

section-B

 Q2) (a) In a diode how the carrier is developed.

(b) Draw the equivalent circuit of Junction Diode

.

Q3) Draw the hybrid model of a low frequency small signal voltage Amplifier.

Q4) Draw and explain the V-I characteristics of JFET.

Q5) A silicon transistor uses potential divider method of Biasing V.. = 12V

R₁ = 10 kΩ, R₂ = 5 kΩ, R₁ = 1 kΩ and R_E = 3 kΩ. Determine the operating point using The venin’s theorem.

 Q6) For class A, CE, amplifier circuit shown in Figure (V_CE)r=10V and

(I_C ), =500mA. If the output current varies by +250mA when an input signal  is applied at the Base, compute the collector efficiency and over all efficiency.

Section - C

Q7) (a) Why the transistor circuit requires stabilization?

(b) Derive the stability factor(s) for voltage division method.

Q8) (a) Draw the circuit of a class 'B' push-pull amplifier and explain its operation

(b) Derive the voltage distortion in push-pull amplifier.

Q9 Derive the expression for the frequency of oscillations and condition for sustain oscillations in a Colpitt’s oscillator.

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Electronic Circuits and Devices Question Paper of 3rd Semester ECE16 Download Previous Years Question Paper 3

Electronic Devices & Circuits

(EC-201, DEC-2005)

Note: Section A is compulsory. Attempt any four questions from Section B and any two questions from  Section C.

Section-A

1.

(a) What is the main important difference between the characteristics of a simple switch and those  of an ideal diode?

(b) Compare JFET and MOSFET. Mention at least four points.

(c) What is reverse Recovery Time?

(d) A dc voltage supply provides 60V when output is unloaded. When connected to a load the  output drops to 56V. Calculate the values of voltage regulation.

(e) What is “Dark current” of a photodiode?

(f) What is negative resistance region?

(g) Which two methods makes the collector current constant. Explain them.

(h) What is fold back limiting?

(i) Calculate dc voltage across 1 Kr load for a RC filter (R=120r, C=10m F). The dc voltage across  the initial filter capacitor is 60V.

(j) Draw the piecewise linear equivalent circuit of diode and explain it briefly.

Section-B

2. Explain the working of CMOS Invertor. Also mention the applications and advantages over other  approaches.

3.

(a) Describe the differences between re and hybrid equivalent for a BJT transistor.

(b) For each model, list the conditions under which it should be applied.

4. A full wave bridge rectifier with 120V rms sinusoidal input has a load resistor of 1kΩ.

 (i) If silicon diodes are employed, what is dc voltage available at load?

 (ii) Determine required PIV rating of each diode.

 (iii) Find maximum current through each diode during condition.

 (iv) What is required power rating of each diode?

5. A silicon transistor with β = 100 is to be used in self biasing circuit shown in figure below, such        that  the Q-point corresponds to VCE = 12V and IC = 2m A. Find RE if VCC = 24V and RC = 5KΩ.

Fig.

6.

(a) What is Miller Theorem?

(b) Explain analysis of emitter follower by using this theorem.

Section-C

7.

(a) What is the significant difference between the construction of an enhancement-type MOSFET  and a depletion type MOSFET?

(b) Sketch the circuit of a CS amplifier. Derive the expression for the voltage gain at low  frequencies.

8.

 (a) For a zener diode network shown in below fig. Determine VL , VR, IZ and PZ.

 (b) What do you mean by hot carrier diode? Compare the characteristics of hot carrier and p-n junction diode?

Fig.

9.

 (a) Design a self-bias network using a JFET transistor with IDSS = 8m A and VP = -6V to have a Qpoint at IDQ = 4m A using a supply of 14V. Assume the RD = 3RS and use standard values.

 (b) Discuss the three configurations of FET biasing. Explain any one in detail.

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Electronic Circuits and Devices Question Paper of 3rd Semester ECE16 Download Previous Years Question Paper 2

Roll No.

Total No. of Questions : 091

B.Tech. (Sem. - 3'd)

ELECTRONICS DEVICES & CIRCUITS

SUBJECT CODE : EC - 201

Paper ID : [A0301]

Time : 03 Hours

Instruction to Candidates:

1) Section - A is Compulsory.

2) Attempt any Four questions from Section - B.

3) Attempt any Two questions from Section - C.

Section - A

Q1)

 a) State what do you understand barrier potential across PN junction and also explain its                          significance.

b) Why bridge type rectifier is preferred over a center tap rectifier?

c) How a PN junction posses a capacitance?

d) What do you understand by the collector reverse saturation current?

e) Why an ordinary junction transistor is called bipolar?

f) What is the need of biasing in a transistor?

g) Draw the h-parameter equivalent circuit of,a transistor.

h) What are characteristics of a good amplifier?

i) In what respect FETs better than BJTs?

j) Define all important parameters of JFET.

Section-B

Q2) The load resistance of a centre tapped full wave rectifier is 500fJ and the

necessary voltage is 60 sin(100t). Calculate

(a) peak, average and rms value of current.

(b) ripple factor and

(c) efficiency of the rectifier.

Each diode has an idealized V-I characteristic having slope corresponding to a resistance of 50Ω

Q3) Explain how stabilization of operating point is achieved using potential divider biasing circuit.

Q4) Draw the output characteristics of JFET and explain how it works as a voltage controlled device.

Q5) Disuses analysis of transistor amplifier using h-parameter in CB configuration?

Q6) The interbase resistance for a silicon UJT is 8k Ω and R_B1 = 5k Ω with I_E = 0.

Determine

(a) Rs2 and (b) intrinsic stand-off ratio.

Determine UJT current, stand-off voltage and peak point voltage when a voltage of 15V is applied between the bases. Take V_B = 0.7V.

Section - C

Q7) (a) Draw and explain the drain and transfer characteristics of an n-channel

enhancement MOSFET.

(b) Sketch the circuit of a CS amplifier. Derive the expression for the voltage

gain at low frequencies.

Q8) Define h-parameters. Derive expression for

(a) Voltage gain

(b) Current gain

(c) Input resistance

(d) Output resistance of CE amplifiers using h-parameters.

Q9) Write short notes on two of the following :

(a) Photransister

(b) FET as an amplifier

(c) Miller's theorem.

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Electronic Circuits and Devices Question Paper of 3rd Semester ECE16 Download Previous Years Question Paper 1

Electronic Circuits and Devices

(EC-201, Dec-07)

Section-A

1).

 a). Discuss the behavior of p-n junction diode under forward and reverse biased

conditions.

b). Draw circuit diagram for CC and CE configuration of transistor. Which is having  higher gain and why.

c). State advantages of JFET over BJT.

d). What is operating point? Why is it necessary to stabilize operating point of a

transistor amplifier?

e). What do you understand by class A,B and C power amplifiers.

f). Draw the block diagram of a multistage amplifier having n-stages. Write

expression for its gain (A).

g). State advantages of –ve feedback in amplifiers.

h). What is an oscillator? What are the essential components of feed back LC

oscillator?

i). Differentiate between photo diodes and photo transistor.

j). Define term junction capacitance. Name different type of capacitances diode

posses.

Section-B

2). Define stability factor. Explain with circuit diagram of potential divider method of  biasing in amplifiers.

3). Draw the circuit diagram of a push pull amplifier. Explain its operation. Discuss advantages and disadvantages.

4). What do you mean by coupling of two amplifier stages. Explain with requisite circuit  diagrams the resistance-capacitance coupling scheme.

5). Draw the block diagram of negative feed back amplifier. Derive an expression for the voltage gains of an amplifier of gain (A) when subjected to negative feedback (B).

6). Explain the principal of working of transistor Hartley oscillator. Draw circuit diagram and briefly function of each component.

Section-C

7). Define h-parameters. Derive expression for

 (a) Voltage gain (b) Current gain (c) Input resistance

 (d) Output resistance of CE amplifiers using h-parameters

8). (a) Draw labeled diagram showing constructional features of N-channel MOSFET. Explain principle and working of N-channel MOSFET in briefly explain.

      (b) Distortion in amplifier circuits.

9). Write short notes on two of the following:-

 (a) Thermal runway (d) PIN Diodes

 (c) Effect of –ve feed back on output resistance of an amplifier.

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