Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 3rd Sem Old 131101 Basic Electronics Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?III (Old) EXAMINATION ? WINTER 2019
Subject Code: 131101 Date: 30/11/2019
Subject Name: Basic Electronics
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Answer the following questions:
1) Sketch the piecewise linear characteristics of PN junction diode.
2) What is cut-in voltage? Write approx. value of cut-in voltage for silicon
and germanium diode.
3) Define Thermal resistance.
4) Define Mean life time of a carrier.
5) What do you mean by PIV (Peak Inverse voltage)? Enlist the value of PIV for
different rectifiers.
6) What is depletion region in PN junction diode.
7) Explain Zener breakdown phenomena.
07
(b) Explain the Hall effect and obtain the expression of Hall coefficient. List the
applications of Hall effect.
07
Q.2 (a) Draw and explain bridge rectifier circuit with capacitor filter. Draw necessary
waveforms.
07
(b) The resistivity of intrinsic silicon is 3 ?10
5
?-cm at 30 ?C. Calculate the intrinsic
concentration at 100 ?C. Assume ?n=0.13m
2
/V-sec and ?p=0.05m
2
/V-sec at 30 ?C.
07
OR
(b) A silicon sample is non-uniformly doped with donor impurity of 10
14
m
? 3
. A
current density of 10mA/cm
2
is generated when electric field of 3V/cm is applied
across it. Find the concentration gradient at 27 ?C. Given: ?n=1500 cm
2
/V-sec.
07
Q.3 (a) Draw the circuit of Common Emitter configuration of transistor. Explain input and
output characteristics. Also derive ? = ? / ?+1.
07
(b) For the circuit shown in Figure (1),explain working of the circuit and draw output
waveform for given input signal. Also draw transfer characteristics.
07
OR
Q.3 (a) What is biasing? Why biasing is required for transistor? List biasing methods for
transistor. Draw and explain the circuit of voltage divider biasing
07
(b) The silicon transistor used in the circuit of Figure (2) has VCE(sat)=0.2V,
VBE(sat)=0.8V, VBE(active)= 0.7V, VBE(cut in)=0.5V and ?=100. (I) Show that the
transistor is in saturation. (II) Calculate the value of RE for which the transistor
just comes out of saturation.
07
Q.4 (a) Define stabilization factors; S, S?, and S?. Also derive expressions for S and
S? for self bias transistor circuit.
07
(b) The transistor used in the circuit of Figure (3) has the following parameters: ?????
= 500 ?, ????? = 2.4 ? 10
? 4
, ????? = 60 and ????? = 1/40 k. Calculate : [1]Vo/VS
[2] ?? ?
?? [3] ?? ?
?? . Assume all capacitors to be very large.
07
OR
Q.4 (a) Draw circuit of an idealized class B push pull power amplifier and explain
its operation with the help of necessary waveforms.
07
(b) Calculate the dc bias voltages and currents for the circuit shown in Figure (4). 07
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Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?III (Old) EXAMINATION ? WINTER 2019
Subject Code: 131101 Date: 30/11/2019
Subject Name: Basic Electronics
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Answer the following questions:
1) Sketch the piecewise linear characteristics of PN junction diode.
2) What is cut-in voltage? Write approx. value of cut-in voltage for silicon
and germanium diode.
3) Define Thermal resistance.
4) Define Mean life time of a carrier.
5) What do you mean by PIV (Peak Inverse voltage)? Enlist the value of PIV for
different rectifiers.
6) What is depletion region in PN junction diode.
7) Explain Zener breakdown phenomena.
07
(b) Explain the Hall effect and obtain the expression of Hall coefficient. List the
applications of Hall effect.
07
Q.2 (a) Draw and explain bridge rectifier circuit with capacitor filter. Draw necessary
waveforms.
07
(b) The resistivity of intrinsic silicon is 3 ?10
5
?-cm at 30 ?C. Calculate the intrinsic
concentration at 100 ?C. Assume ?n=0.13m
2
/V-sec and ?p=0.05m
2
/V-sec at 30 ?C.
07
OR
(b) A silicon sample is non-uniformly doped with donor impurity of 10
14
m
? 3
. A
current density of 10mA/cm
2
is generated when electric field of 3V/cm is applied
across it. Find the concentration gradient at 27 ?C. Given: ?n=1500 cm
2
/V-sec.
07
Q.3 (a) Draw the circuit of Common Emitter configuration of transistor. Explain input and
output characteristics. Also derive ? = ? / ?+1.
07
(b) For the circuit shown in Figure (1),explain working of the circuit and draw output
waveform for given input signal. Also draw transfer characteristics.
07
OR
Q.3 (a) What is biasing? Why biasing is required for transistor? List biasing methods for
transistor. Draw and explain the circuit of voltage divider biasing
07
(b) The silicon transistor used in the circuit of Figure (2) has VCE(sat)=0.2V,
VBE(sat)=0.8V, VBE(active)= 0.7V, VBE(cut in)=0.5V and ?=100. (I) Show that the
transistor is in saturation. (II) Calculate the value of RE for which the transistor
just comes out of saturation.
07
Q.4 (a) Define stabilization factors; S, S?, and S?. Also derive expressions for S and
S? for self bias transistor circuit.
07
(b) The transistor used in the circuit of Figure (3) has the following parameters: ?????
= 500 ?, ????? = 2.4 ? 10
? 4
, ????? = 60 and ????? = 1/40 k. Calculate : [1]Vo/VS
[2] ?? ?
?? [3] ?? ?
?? . Assume all capacitors to be very large.
07
OR
Q.4 (a) Draw circuit of an idealized class B push pull power amplifier and explain
its operation with the help of necessary waveforms.
07
(b) Calculate the dc bias voltages and currents for the circuit shown in Figure (4). 07
2
Q.5 (a) Derive expressions for AI, Ri, AV, and Yo in terms of CE h-parameters for emitter
follower circuit.
07
(b) Draw and explain working of diode compensation circuit for VBE for self-
stabilization in amplifier circuit.
07
OR
Q.5 (a) Draw structure of n-channel JFET and explain its working. 07
(b) Draw a structure of p-channel MOSFET. Explain its working for enhancement
type. Also draw and explain drain characteristics and transfer curve for the same
device.
07
*************
Figure (2)
Figure (1)
Figure (3)
Figure (4)
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This post was last modified on 20 February 2020