SAGAR INSTITUTE OF SCIENCE & TECHNOLOGY (SISTec) Gandhinagar, BHOPALDepartment of Electronics & Communication

Pre-University Test (Nov, 2012)SEM: III SUB: Electronic Devices CODE: EC-304 Time: 3 Hr Max. Marks: 70NOTE: Attempt any one question from each unit and each question carry equal mark.

UNIT-I

Q: 1 a) Explain Hall Effect. Derive the expression for Hall voltage. b) The hall effect experiment used for a silicon bar known to be P type , the resistivity is 220×10-3 Ω-cm, width is 2mm and distance between two surfaces is 2.2 mm. The magnetic field used has intensity of 0.1 wb/m2 . if the measured current I and hall voltage VH are 5 µA & 28 mV respectively. Calculate (i) mobility (ii) Electric field intensity, E (iii) current density J (iv) RH.

OR

Q: 2 a) With reference to PN junction define following :

(i) Barrier Potential (ii Depletion Layer (iii) Breakdown process

(iv) Reverse current

b) Explain transition and diffusion capacitance.

UNIT-2

Q: 3 a) b)

ORQ: 4 a) b)

UNIT-3Q: 5 a) Explain telemetry, tracking and command (TT & C) subsystem for satellite. 10 b) Explain working of satellite transponder with proper block diagram. 10 ORQ: 6 a) Explain working of receive only home TV system. 10 b) Explain working of transmit-receive earth station. 10

UNIT-4

Q: 7 a) Define EIRP. Derive an expression of Equivalent Isotropic Radiated power (EIRP). 10 b) Explain link power budget equation for satellite link. 10

ORQ: 8 a) Explain intermodulation noise in satellite link. How it can reduced? 10 b) Explain C/N for uplink and downlink of satellite. 10

UNIT-5Q: 9 a) Explain network architecture of VSAT system. 10 b) Explain VSAT earth station with help of block diagram. 10 ORQ: 10 a) Explain the installation of DBS-TV antenna. 10

b) Explain error control in of digital DBS-TV. 10 SAGAR INSTITUTE OF SCIENCE & TECHNOLOGY (SISTec)

Gandhinagar, BHOPAL Department - Electronics and communication

Mid Semester Test -1 SEM: III SUB: Electronic Devices CODE: EC-304

Time: 1 Hr 30 Minutes Max. Marks: 50

NOTE: Figures to the right indicate maximum marks.

Q: 1 a) 10b)c)

Explain the diffusion and drift current.

OR

0604

Q: 2 a) 10

b) 10Q: 3 a) Explain in details, classification of semiconductors. Also draw energy

band diagram in each case.10

b) Define following parameters w.r.t Rectifier: (a) Rectifier efficiency (b) PIV (C) TUF (d) % Voltage Regulation

OR

10

Q: 4 a) With the help of neat diagram, explain V-I Characteristics of PN junction diode.

07

b)

c)

Define cut in voltage for a diode. A Silicon diode has reverse saturation Current of 2.5 µA at 300OK. Find the forward voltage for forward current of 10 mA. With the help of neat diagram and waveform, explain working of bridge rectifier.

0706

Q: 5 a) Compare the different parameters of half and full wave rectifier 05b) Define ripple factor and find its value for half wave rectifier. 05

SAGAR INSTITUTE OF SCIENCE & TECHNOLOGY (SISTec)Gandhinagar, BHOPAL

Department - Electronics and communication Mid Semester Test -2

SEM: III SUB: Electronic Devices SUB CODE: EC-304

Time: 1 Hr 30 Minutes Max. Marks: 50

NOTE: Figures to the right indicate maximum marks.

Q: 1 a) Explain the construction, working & characteristics of Tunnel diode. 10

b) Explain the construction, working & characteristics of PIN Diode.OR

10

Q: 2 a) Explain Zener diode as voltage regulator. 10

b) Find the range of Vin that will maintain Zener diode in ON state. 10

Q: 3 a) Explain the construction and working principle of Transistor. 10

b) Define α and β of BJT. Derive an expression for α in terms of β.Also compare the three transistor configurations for various parameters.

OR

10

Q: 4 a) Draw and explain the common emitter input and output characteristics of a transistor.

10

b) Determine following for a given network:(a) IB (b) VCE (c) VB (d) VC

10

Q: 5 Write short note on (a) LED (b) Schottky diode

05x2=10