Electronic Devices And Circuits Jntu Model Paper{Www.Studentyogi.Com}

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Code No: 07A1EC06
Set No. 1
I B.Tech Regular Examinations, May/Jun 2008
ELECTRONIC DEVICES AND CIRCUITS
( Common to Electronics & Communication Engineering, Computer Science
& Engineering, Electronics & Instrumentation Engineering, Bio-Medical
Engineering, Information Technology, Electronics & Control Engineering,
Computer Science & Systems Engineering, Electronics & Telematics,
Electronics & Computer Engineering and Instrumentation & Control
Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks

1. In a parallel place dio de, the cathode and anode are spaced 5mm apart and the
anode is kept at 200V d.c. with respect to cathode. Calculate the velocity and the
distance travelled by an electron after a time of 0.5ns, when [16]

(a) The initial velocity of an electron is zero and
(b) The initial velocity is 2×106 m/s in the direction towards the anode.

2. (a) Explain the volt ampere characteristics of PN diode.
(b) Explain the temperature dependence of VI characteristics. [8+8]

3. Determine:
(a) DC output voltage,
(b) PIV,

(c) Recti cation e eminacy of the given circuit gure3c. [16]


Code No: 07A1EC06
Set No. 1
4. Explain the input and output characteristics of common base transistor con gura-
tion. [16]

5. (a) Explain the criteria for xing operating point.
(b) List out the di erent types of biasing methods. [12+4]

6. (a) Write a short notes on millers theorem.
(b) Analyse a single stage transistor ampli er using h - parameters. [8+8]

7. With neat sketch explalin about all types of feedback systems. [16]

8. (a) De ne:
i. Damped Oscillation
ii. Un Damped oscillation.
(b) Why an LC tank circuit, once excited, does not produce sustained oscillation?
Explain it brie y?
(c) Give the two Bark Hansen condition required for sinusoidal oscillations to be
sustained.
(d) What are the factors which a ect the frequency stability of an oscillator?
[4+6+2+4]


Code No: 07A1EC06
Set No. 2
Engineering)

1. Derive the expression for the de ection in an electrostatic de ection system. Hence
obtain the expression for electro static de ection sensitivity. [16]

2. (a) De ne law of junction.
(b) Explain the Fermi’s level in intrinsic semiconductor. [6+10]

3. (a) Draw the circuit diagram of HWR. Explain its working. What is the frequency
of ripple in its output
(b) A HWR circuit supplies 100mA d.c to a 250 load. Find the d.c output
voltage, PIV rating of a diode and the r.m.s. voltage for the transformer
supplying the recti er. [8+8]

4. (a) How the UJT di ers from ordinary PN diode.
(b) Explain the construction of UJT.
(c) Draw and explain the equivalent circuit of UJT. [4+6+6]

5. (a) Explain the criteria for xing operating point.
(b) List out the di erent types of biasing methods. [12+4]

6. (a) Draw the low frequency hybrid equivalent. Circuit for CE & CB ampli er.
(b) Give the approximate h-parameter conversion formulae for CB and CC con-
guration in terms of CE.
(c) Give the advantages of h-parameter analysis.
(d) Give the procedure to form the approximate h - mo del from exact h - model
of ampli er. [4+6+3+3]

7. Compare the impedance levels of a voltage series feedback ampli er before and
after feedback. [16]

8. Explain brie y about frequency and amplitude stability of oscillators. [16]


Code No: 07A1EC06
Set No. 3
Engineering)

1. What are the front panel controls of CRO? Explalin. [16]

2. (a) Short notes on LED voltage drop and current.
(b) Write short notes on Multi colour LED. [10+6]

3. Draw the circuit diagram of a FWR:

(a) With centre tap connection and
(b) Bridge connection and explain its operation. [16]

4. (a) Write short notes on Emitter e ciency.
(b) Write short notes on Transport factor.
(c) Large signal current gain. [5+5+6]

5. If the various parameters of a CE ampli er which uses the self bias etho d are CC
= 12 V, 1 = 10 k , 2 = 5k?, RC 1 k , e =2 K and = 100, nd

(a) The coordinates of the operating point, and
(b) The stability factor, assuming the transistor to be of silicon. [16]

6. (a) Compare V i i& 0 of CE, CB and CC con guration.

(b) The h-parameters of a transistor used in a CE circuit are ie = 1.0 K , re
= 10×10-4, fe = 50, oe = 100 K. The load resistance for the transistor is
1 K in the collector circuit. Determine i o V i in the ampli er stage
(Assume s = 1000 ). [4+12]

7. With neat sketch explalin about all types of feedback systems. [16]

8. Explain brie y about frequency and amplitude stability of oscillators. [16]


Code No: 07A1EC06
Set No. 4
Engineering)

1. Analyse the motion of an electron under perpendicular electric and magnetic elds.
[16]

2. (a) Explain about semiconductor, Insulator & Conductor with neat sketch.
(b) State the Einstein relationship for semiconductor.
(c) State paulis exclusion principle. [6+5+5]

3. A voltage of 200 cos wt is applied to HWR with load resistance of 5 K . nd the
maximum d.c current component, r.m.s. current, ripple ractor, TUF and recti er
e ciency. [16]

4. (a) De ne a Transistor.
(b) What are the di erences between Bipolar Junction transistor & Field e ect
Transistor?
(c) Write any two applications of transistor. [5+7+4]

5. (a) Explain the simpler way of drawing dc load line.
(b) Calculate the de bias voltage and currents in the circuit shown in gure 5b
(Neglect BE Of Transistor). [8+8]


Code No: 07A1EC06
Set No. 4

Figure 5b
6. (a) Draw the low frequency hybrid equivalent. Circuit for CE & CB ampli er.
(b) Give the approximate h-parameter conversion formulae for CB and CC con-
guration in terms of CE.
(c) Give the advantages of h-parameter analysis.
(d) Give the procedure to form the approximate h - mo del from exact h - model
of ampli er. [4+6+3+3]

7. Draw the practical circuit for Current series feedback and nd the voltage gain,
input impedance & output impedance. [16]

8. (a) A wein bridge oscillator has a frequency of 500Hz, if the value of C is 100Pf,
determine the value of R.
(b) List the advantages of wein-bridge oscillator. [10+6]

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Electronic Devices And Circuits Jntu Model Paper{Www.Studentyogi.Com}