Thapar University 2006 B.E Electronic Instrumentation & Control Engineer Semiconductor Devices - Question Paper
Thapar Institute of Engineering & Technology
B.Tech Electrical & Instrumentation (2ndYear)
Final Term exam
ES202 (Semiconductor Devices)
THAPAR INSTITUTE OF ENGINEERING AND TECHNOLOGY, PATIALA
END SEMESTER EXAMINATION, Dec 2006 ( m)
SEMICONDUCTOR DEVICES (ES 202)
Time allowed : 3 hrs M.M: 36
NOTE:Attempt any six questions out of eight
Attempt parts of the same question in sequence Assume any missing data suitably See your answer sheets on 16 December, 2006 at 5.00 PM in L-212 (ECE deptt)
1.Q a) Explain the V-I characteristics of an ideal and practical PN junction diode with diagram. (3)
b) Find the concentration of holes and electrons in P type Si at 300K if a = 100 (ohm cm)*1. ni= 1.5xl0I0/cm3,Hp=500cm2/Vs,fin=1300cm2/Vs. (1.5)
c) Explain voltage regulation in Zener Diode? Draw the circuit Diagram also. (1.5)
2.Q a) Explain input and output characteristics of a CB transistor with properly labeled diagrams defining all the regions properly. (4) b) Explain transistor switching with diagrams clearly showing all the different time parameters involved. (2)
3.Q a) Define the stability factor, S? (1)
b) Define thermal runaway? (1)
c)'Explain early effect in transistors? (1)
d) A pnp transistor with p = 50 is used in CE configuration with Vcc=10V, Rc= 2Kohm. The bias is obtained by connecting a lOOKohm resistor from Collector to base. Assume VBE=0V. Calculate S. (1)
e) Draw the DC load line for the fixed bias CE configuration if Rc = 80 ohm,Vcc =24V. (2)
4.Q a) Derive the following parameters of a transistor amplifier using h-parameters
i) Current gain, A] ii) Voltage Gain, Ay iii) Input Impedance, Zj iv) Output admittance,Y0
(4)
b) In a CB transistor amplifier hjb= 30 ohm, h,b = 4xl0'6 , hfb= -0.99 , hob= 8xl0'7 (ohm)'1, Rl=Rs=20K ohm. Find A(, Av, Zj ,Y0 (2)
5.Q a) Explain the enhancement type MOSFET with construction and drain characteristics.
(4)
b) A JFET has Vp= -4.5 V, Idss~ 10mA, Ids= 2.5mA. Determine VqS (1)
c) Why FETs are called unipolar devices. (1)
6.Q a) Explain full wave rectifier working with neatly labeled diagram. Derive the ripple factor and efficiency for this. (4) b) Find the value of inductance to use the inductor filter connected to a full wave rectifier operating at 60 HZ to provide a DC output with 4% ripple factor for a 100 ohm load. (2)
7.Q a) Explain the hybrid pi CE transistor model with suitable diagram. (3)
b) Explain the linear 1C regulators? (3)
8.Q Write short notes (with diagrams wherever necessary)
a) Intrinsic and extrinsic semiconductor
b) 7t filter
c) Depletion and transition capacitance of a diode. (2+2+2)
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| Earning: Approval pending. |
