Jawaharlal Nehru Technological University Hyderabad 2005 B.E Computer Science ELECTRONIC DEVICES & CIRCUITS I B.TechRegular s, set 3 - Question Paper

Code No: RR10205 Set No.3
I B.Tech. Regular Examinations, June 2005
ELECTRONIC DEVICES & CIRCUITS
( Common to Electrical & Electronic Engineering, Electronics &
Communication Engineering, Computer Science & Engineering, Electronics
& Instrumentation Engineering, BioMedical
Engineering, info
Technology, Electronics & Control Engineering, Computer Science &
Systems Engineering, Electronics & Telematics, Electronics & Computer
Engineering and Instrumentation & Control Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. Compare the motion and trajectories of electron when placed
(a) Only in electric fields
(b) Only in magnetic fields
(c) Combined electric & Magnetic fields.[6+6+4]
2. (a) discuss the term reverse saturation current in the case of a pn
junction diode.
(b) Derive the expression for Io in a pn
junction diode.[8+8]
3. (a) explain a full wave rectifier with P filter.
(b) Compare the performance of inductive, Lsection
and P part filters.[8+8]
4. (a) Why transistor is considered as current control device. discuss.
(b) In a transistor if emitter junction is forward biased and collector is reverse
bias discuss its operation.
(c) discuss why a < one and b > one for a provided transistor.[6+6+4]
5. (a) provide the UJT symbol and simplified equivalent circuit with external resistors
included.
(b) Draw UJT emitter characteristics and mention different region.
(c) If VE < Vp and VE > Vp for these condition how UJT works.
(d) If h =0.8 VBB = 15V and VD = 0.7V. obtain the value of Vp[4+4+4+4].
6. (a) Draw the circuit diagram of a collector to base bias circuit of CE amplifier
and derive expression for S.
(b) Determine the quiescent currents and the collector to emitter voltage for a
germanium transistor with b =50 in self biasing arrangement. Draw the circuit
with a provided component value VCC = 20V, RC = 2K, Re = 100 R1 =
100KW R2 = 5K. Also obtain out stability factor.[8+8]
7. (a) Sate and discuss Barkhausen criterion. elaborate the 4 topologies of feedback
amplifier. discuss taking sampling and mixing signals to every topology.
(b) State transfer gain of every configuration and describe feedback factor.[8+8]
8. (a) Draw the circuit diagram of a RC phases shift oscillator using BJT. Derive
the expression for frequency of oscillators.
(b) Classify various kind of oscillators based on frequency range.
(c) Why RC oscillators are not suitable for high frequency applications.[6+6+4]

Earning:   Approval pending.